Short answer
Be a real friend, whether or not your friend ever becomes Muslim. Listen first, and ask what brought them to their view. Start from reason and from what your friend already accepts. Give reasons anyone can test before you quote verses. Take one argument at a time, and say so when you do not know. Speak gently (20:44). Never mock, and never say atheists are immoral or secretly believe. Do not bring up history or politics yourself. If your friend asks if you are trying to convert them, the honest answer is no: you cannot, for only God (﷾) guides hearts (28:56). You are making them aware of Islam in a friendly discussion, not a debate, and the choice is theirs (2:256). If their answer is no, end as Muslims are taught: "To you be your Way, and to me mine" (109:6). Then keep the friendship.
Full explanation
Be a true friend first
This guide is for talking with friends who do not believe in God (﷾), or who are not sure. Be a real friend, whether or not your friend ever becomes Muslim. Never befriend someone only to convert them. The Qur'an allows Muslims to deal kindly and justly with those who do not fight them over faith. It says that God (﷾) loves the just. It also commands justice to everyone, even towards people who hate them (5:8). Guidance is God's (﷾) to give, not yours. The Qur'an tells the Prophet (ﷺ), "thou wilt not be able to guide every one, whom thou lovest". Your part is to speak clearly and kindly, and to stay a friend whatever the answer.
“Allah forbids you not, with regard to those who fight you not for (your) Faith nor drive you out of your homes, from dealing kindly and justly with them: for Allah loveth those who are just.”
“It is true thou wilt not be able to guide every one, whom thou lovest; but Allah guides those whom He will and He knows best those who receive guidance.”
“Let there be no compulsion in religion: Truth stands out clear from Error: whoever rejects evil and believes in Allah hath grasped the most trustworthy hand-hold, that never breaks. And Allah heareth and knoweth all things.”
“O ye who believe! stand out firmly for Allah, as witnesses to fair dealing, and let not the hatred of others to you make you swerve to wrong and depart from justice. Be just: that is next to piety: and fear Allah. For Allah is well-acquainted with all that ye do.”
Listen first
People come to atheism by different roads. Some turned away after a bad experience of religion, such as a harsh teacher or a hypocrite who preached. Some reasoned their way there from science or philosophy. Some lost someone they loved and could not see why God (﷾) allowed it. Some never had a faith at all. Do not guess which road your friend took. Ask, and listen to the whole answer. Ask, too, what your friend means by "atheist". Some mean they are sure there is no God. Others mean only that they are not persuaded. If your friend was hurt by religious people, say plainly that you are sorry. Then let the conversation go where your friend wants.
“Invite (all) to the Way of thy Lord with wisdom and beautiful preaching; and argue with them in ways that are best and most gracious: for thy Lord knoweth best, who have strayed from His Path, and who receive guidance.”
“It is part of the Mercy of Allah that thou dost deal gently with them Wert thou severe or harsh-hearted, they would have broken away from about thee: so pass over (Their faults), and ask for (Allah's) forgiveness for them; and consult them in affairs (of moment). Then, when thou hast Taken a decision put thy trust in Allah. For Allah loves those who put their trust (in Him).”
Start from reason and what your friend accepts
For your friend, a verse of the Qur'an is not yet evidence. So do not open with verses. Start from what your friend already accepts: that reasoning matters, and that the world is really there. Then ask the big questions. Why is there something rather than nothing? Can a thing that depends on something else be the end of all explanation? If the mind came only from matter, why trust its reasoning? Is anything really evil, or is it only disliked? Offer reasons strong enough to leave no reasonable doubt, and do not claim more than you have shown. Faith itself grows into certainty (yaqin). What you offer a friend is reasons they can test. When a reason has landed, you can add that Islam says the same. The Qur'an itself argues by questions: "Were they created of nothing, or were they themselves the creators?"
Divides all that exists into what is only possible in itself (mumkin al-wujud), which needs a cause, and what is necessary in itself (wajib al-wujud), which needs none. Argues that a chain of possible things, however long, needs a necessary being outside it, and that this being is one and has no parts.
Argues that the sufficient reason for the whole series of contingent things must lie outside that series, in a necessary substance, which Leibniz calls God.
“A wise man, therefore, proportions his belief to the evidence.”
“Were they created of nothing, or were they themselves the creators? Or did they create the heavens and the earth? Nay, they have no firm belief.”
One argument at a time
Take one question and follow it to the end before you start another. A list of ten quick arguments convinces no one. Let your friend raise objections, and treat each one seriously. If you do not know an answer, say so, and offer to find out. The Qur'an says, "pursue not that of which thou hast no knowledge". Check your facts before you share them, and never pass on a claim you cannot source. You are not trying to win. Stop when your friend has had enough, and pick it up another day.
“And pursue not that of which thou hast no knowledge; for every act of hearing, or of seeing or of (feeling in) the heart will be enquired into (on the Day of Reckoning).”
“Invite (all) to the Way of thy Lord with wisdom and beautiful preaching; and argue with them in ways that are best and most gracious: for thy Lord knoweth best, who have strayed from His Path, and who receive guidance.”
Gentle words, never mockery
God (﷾) sent Musa and Harun (Moses and Aaron) to Pharaoh, a tyrant who told his people, "I am your Lord, Most High". Even so, He told them, "speak to him mildly". If that was the command for a tyrant, a friend is owed gentleness all the more. The Qur'an tells Muslims to invite "with wisdom and beautiful preaching". It tells them to argue "in ways that are best and most gracious". It forbids them even to revile what others worship besides God (﷾). So never mock your friend's view, or laugh at an argument. The Prophet (ﷺ) told Aisha to be gentle, for God (﷾) loves gentleness in every matter. He said he was not sent to curse, but as a mercy.
“"But speak to him mildly; perchance he may take warning or fear (Allah)."”
“Then he collected (his men) and made a proclamation, Saying, "I am your Lord, Most High".”
“Invite (all) to the Way of thy Lord with wisdom and beautiful preaching; and argue with them in ways that are best and most gracious: for thy Lord knoweth best, who have strayed from His Path, and who receive guidance.”
“Revile not ye those whom they call upon besides Allah, lest they out of spite revile Allah in their ignorance. Thus have We made alluring to each people its own doings. In the end will they return to their Lord, and We shall then tell them the truth of all that they did.”
Aisha reports that some Jews greeted the Prophet (ﷺ) with "death be upon you", and she cursed them in return. He told her to be gentle, for Allah loves gentleness in every matter. When she asked whether he had not heard what they said, he replied that he had answered them only with "and upon you".
Abu Hurayra reports that someone asked the Messenger of Allah (ﷺ) to curse the polytheists. He answered that he had not been sent as one who curses, but as a mercy.
Never judge your friend's heart
Do not say, or hint, that your friend secretly believes in God (﷾). Do not call atheists immoral or insincere. Speak about arguments, never about a person's motives. Islam teaches that every child is born upon the fitra, an inborn leaning to know the one Maker. That is a teaching about all people, you included. It is not a charge against your friend. Do not use it to tell someone what is in their heart. Only God (﷾) knows that. Do not generalise about atheists either, kindly or unkindly. Speak to the friend in front of you.
Abu Hurayra reports that the Prophet (ﷺ) said every child is born upon the fitra, the true faith, and it is his parents who make him a Jew, a Christian or a Magian, just as an animal gives birth to a whole young one: do you see any of them born mutilated?
“So set thou thy face steadily and truly to the Faith: (establish) Allah's handiwork according to the pattern on which He has made mankind: no change (let there be) in the work (wrought) by Allah: that is the standard Religion: but most among mankind understand not.”
Common ground: honesty, evidence and wonder
Your friend may care about honesty, about evidence, and about not believing things just because others do. Islam values all three. The Qur'an tells people not to follow what they have no knowledge of. It does not ask for blind faith. It calls on people to look at the heavens and the earth: "there are indeed Signs for men of understanding". Your friend may also feel wonder at the universe, or at the order science uncovers. Tell your friend sincerely that you share these values. Then say gently where Islam differs. In Islam, honesty, evidence and wonder lead somewhere: to the One who made the world and the mind that studies it.
“And pursue not that of which thou hast no knowledge; for every act of hearing, or of seeing or of (feeling in) the heart will be enquired into (on the Day of Reckoning).”
“Behold! in the creation of the heavens and the earth, and the alternation of night and day,- there are indeed Signs for men of understanding,- Men who celebrate the praises of Allah, standing, sitting, and lying down on their sides, and contemplate the (wonders of) creation in the heavens and the earth, (With the thought): "Our Lord! not for naught Hast Thou created (all) this! Glory to Thee! Give us salvation from the penalty of the Fire.”
If your friend grew up in a Muslim home
Some friends grew up in a Muslim family and now doubt. Be especially gentle with them. Do not lecture, and do not quarrel. Ask what troubled them, and listen to the whole answer. Do not guess: for some it was one hard question, for others many. Doubts can be answered, one at a time, from the sources. The site's path "When doubts come" was written for that. Keep the friendship warm whatever your friend says.
“Invite (all) to the Way of thy Lord with wisdom and beautiful preaching; and argue with them in ways that are best and most gracious: for thy Lord knoweth best, who have strayed from His Path, and who receive guidance.”
“It is part of the Mercy of Allah that thou dost deal gently with them Wert thou severe or harsh-hearted, they would have broken away from about thee: so pass over (Their faults), and ask for (Allah's) forgiveness for them; and consult them in affairs (of moment). Then, when thou hast Taken a decision put thy trust in Allah. For Allah loves those who put their trust (in Him).”
If history or politics comes up
Do not bring up history or politics yourself. Your aim is to talk about God (﷾), not to argue about the past or about governments. If your friend raises the news, listen kindly. Say honestly that you would rather talk about the big questions, and return to them. If your friend raises a wrong that some Muslims did, say plainly that it was wrong. Do not defend it, and do not blame anyone else. A faith is judged by its teaching, not by what some followers did. That fair rule holds for every faith. Do not answer with numbers of deaths blamed on others. The Qur'an commands justice, "even as against yourselves". The Prophet (ﷺ) was told to say: "This is my way: I do invite unto Allah".
“O ye who believe! stand out firmly for justice, as witnesses to Allah, even as against yourselves, or your parents, or your kin, and whether it be (against) rich or poor: for Allah can best protect both. Follow not the lusts (of your hearts), lest ye swerve, and if ye distort (justice) or decline to do justice, verily Allah is well-acquainted with all that ye do.”
“Say thou: "This is my way: I do invite unto Allah,- on evidence clear as the seeing with one's eyes,- I and whoever follows me. Glory to Allah! and never will I join gods with Allah!"”
“Invite (all) to the Way of thy Lord with wisdom and beautiful preaching; and argue with them in ways that are best and most gracious: for thy Lord knoweth best, who have strayed from His Path, and who receive guidance.”
What not to use
Some arguments people use are unsound. Leave them out, because a Muslim says only what he knows to be true (17:36). Never say that your friend secretly believes. Do not say that science proves God (﷾), for example from research on how children think. Do not make Pascal's wager (the bet that believing is the safer choice) your proof. Do not trade numbers of deaths blamed on religion or on atheist governments. Do not quote surveys of scientists or philosophers. Do not offer any famous person's change of mind as proof. And never claim more certainty than you have shown. Other points are a matter of order. Do not build your case on contested readings that match verses to modern science. The Qur'an is a book of guidance, and the talk would turn to the science instead of to God (﷾). Do not open with the splitting of the moon, or other miracles of the prophets. The moon was split: the Qur'an states it (54:1), and so do authentic hadith. But your friend does not yet accept the Qur'an and hadith as sources, so give reasons first. Begin with reason, and with the Qur'an itself as a book anyone can test.
“And pursue not that of which thou hast no knowledge; for every act of hearing, or of seeing or of (feeling in) the heart will be enquired into (on the Day of Reckoning).”
“The Hour (of Judgment) is nigh, and the moon is cleft asunder. But if they see a Sign, they turn away, and say, "This is (but) transient magic."”
Anas ibn Malik reports that the people of Mecca asked the Messenger of Allah to show them a sign, and he showed them the moon split.
“And if ye are in doubt as to what We have revealed from time to time to Our servant, then produce a Sura like thereunto; and call your witnesses or helpers (If there are any) besides Allah, if your (doubts) are true.”
Pages to read together
This site has pages written for atheists and agnostics. Share the one that fits your friend's question. For who has to prove what, read "Who has to prove it: the believer or the atheist?" Then try "If everything needs a creator, who created God?" and "Why is there something rather than nothing?" For a friend who is unsure, read "Can we know if God exists?" and "If I'm not sure about God, what should I do?" For suffering: "Why does God allow suffering?" and "Why doesn't God make Himself obvious?" For morality: "If there is no God, can anything really be evil?" For science: "Does evolution disprove God?" and "Can I believe in science instead of religion?" Also useful: "Aren't we all atheists about other gods?" and "Is it fair that Hell lasts for ever?" The site's paths "For atheists: the case for God" and "For agnostics: can we know?" take these in order. Whatever you read, come back to one question: is all this for nothing? The Qur'an gives the answer of those who reflect: "Our Lord! not for naught Hast Thou created (all) this!" For yourself, the site's Dawah guide sets out the whole method.
“Behold! in the creation of the heavens and the earth, and the alternation of night and day,- there are indeed Signs for men of understanding,- Men who celebrate the praises of Allah, standing, sitting, and lying down on their sides, and contemplate the (wonders of) creation in the heavens and the earth, (With the thought): "Our Lord! not for naught Hast Thou created (all) this! Glory to Thee! Give us salvation from the penalty of the Fire.”
Islam's answer, and your part
In the end, invite your friend to Islam itself. Islam is a complete way of life (deen): belief, worship, law, family and character together. The page "What do Muslims believe?" shows it in one place. The Qur'an asks to be tested: produce a chapter like it. It says the Prophet (ﷺ) was sent to all people, and calls him the Seal of the Prophets, the last of them. Your part is to speak clearly and kindly. There is no compulsion in religion, so the choice is your friend's. Who is better in speech than one who calls to God (﷾) and does good? Inviting is your part; guiding a heart is God's (﷾) alone. That is why, if your friend asks whether you are trying to convert them, the honest answer is no.
“This day have I perfected your religion for you, completed My favour upon you, and have chosen for you Islam as your religion.”
“O ye who believe! Enter into Islam whole-heartedly; and follow not the footsteps of the evil one; for he is to you an avowed enemy.”
“And if ye are in doubt as to what We have revealed from time to time to Our servant, then produce a Sura like thereunto; and call your witnesses or helpers (If there are any) besides Allah, if your (doubts) are true.”
“Say: "O men! I am sent unto you all, as the Messenger of Allah, to Whom belongeth the dominion of the heavens and the earth: there is no god but He: it is He That giveth both life and death. So believe in Allah and His Messenger, the Unlettered Prophet, who believeth in Allah and His words: follow him that (so) ye may be guided."”
“Muhammad is not the father of any of your men, but (he is) the Messenger of Allah, and the Seal of the Prophets: and Allah has full knowledge of all things.”
“Let there be no compulsion in religion: Truth stands out clear from Error: whoever rejects evil and believes in Allah hath grasped the most trustworthy hand-hold, that never breaks. And Allah heareth and knoweth all things.”
“Who is better in speech than one who calls (men) to Allah, works righteousness, and says, "I am of those who bow in Islam"?”
“It is true thou wilt not be able to guide every one, whom thou lovest; but Allah guides those whom He will and He knows best those who receive guidance.”
What your friend may say
The Presumption of Atheism (1972)
Proposes that a debate about God should begin from a presumption of atheism, with the burden of proof on the theist. Reads "atheist" as "not a theist" (the negative atheist), and names the person who asserts that there is no God the positive atheist.
Cited for
There is no evidence for God, so I don't believe.
The response
Then let's look at the evidence together, one piece at a time. Everything around us depends on something else. A chain of things that depend needs something that depends on nothing. Do you think that holds? If not, tell me where it breaks. I am not asking you to take a verse on trust. I am asking you to weigh a reason.
Where it lands — The question moves from who must prove it to what the evidence shows, one reason at a time.
Qur'an 67:2 — Surat al-Mulk (The Sovereignty), verse 2
“He Who created Death and Life, that He may try which of you is best in deed: and He is the Exalted in Might, Oft-Forgiving;-”
Cited for
If there is a God, why is there so much suffering?
The response
That is a serious question, and I don't want to give a quick answer. Has suffering touched you or someone close to you? Islam says this life is a test: God (﷾) "created Death and Life, that He may try which of you is best in deed". It also says God (﷾) will "set up scales of justice", and that He is "never unjust in the least degree". Can we read about it together?
Where it lands — The friend's own experience comes first, and Islam's answer follows without haste.
Qur'an 16:97 — Surat al-Nahl (The Bee), verse 97
“Whoever works righteousness, man or woman, and has Faith, verily, to him will We give a new Life, a life that is good and pure and We will bestow on such their reward according to the best of their actions.”
Cited for
I can be a good person without God.
The response
Yes, people do good without believing in God (﷾), and I would never say you are not a good person. My question is different: what makes good really good, and not just a feeling we share? If there is no God, can anything be truly evil? Islam's answer is that the One who made each soul showed it "its wrong and its right". Whoever does good and has faith, He promises "a life that is good and pure".
Where it lands — Goodness is welcomed, and the question of what grounds it still stands.
Qur'an 4:135 — Surat al-Nisa (The Women), verse 135
“O ye who believe! stand out firmly for justice, as witnesses to Allah, even as against yourselves, or your parents, or your kin, and whether it be (against) rich or poor: for Allah can best protect both. Follow not the lusts (of your hearts), lest ye swerve, and if ye distort (justice) or decline to do justice, verily Allah is well-acquainted with all that ye do.”
Cited for
Religion has caused so much harm in the world.
The response
Where people did wrong in God's (﷾) name, it was wrong, and I won't defend it. A faith is judged by its teaching, not by what some followers did. That is the fair rule for every faith. The Qur'an commands justice, "even as against yourselves". So let's come back to the big question: is there a God, and has He spoken?
Where it lands — Wrongs are called wrong, and the conversation returns to the big question: is there a God, and has He spoken?
Qur'an 17:15 — Surat al-Isra (The Night Journey), verse 15
“Who receiveth guidance, receiveth it for his own benefit: who goeth astray doth so to his own loss: No bearer of burdens can bear the burden of another: nor would We visit with Our Wrath until We had sent a messenger (to give warning).”
Cited for
So do you think I'm going to Hell?
The response
I can't say where anyone will end; no Muslim may declare any particular person's fate. That belongs to God (﷾). But I won't hide what Islam teaches. Hell is real, and it is for ever for those who die rejecting faith after the message has reached them. God (﷾) sends no wrath "until We had sent a messenger", and He is "never unjust in the least degree". Who has truly received the message, and how a life will end, only God (﷾) knows. The door stays open until death.
Where it lands — Islam states its teaching openly, judges no one's fate, and leaves each person to a God who wrongs no one.
Qur'an 17:15 — Surat al-Isra (The Night Journey), verse 15
“Who receiveth guidance, receiveth it for his own benefit: who goeth astray doth so to his own loss: No bearer of burdens can bear the burden of another: nor would We visit with Our Wrath until We had sent a messenger (to give warning).”
Cited for
If people who never heard may be safe, why are you telling me?
The response
We do not say anyone is safe or lost; that is for God (﷾), who knows what reached each person. But the message is now reaching you. The Qur'an says: "Who receiveth guidance, receiveth it for his own benefit: who goeth astray doth so to his own loss". I tell you because I believe it is true, and I want that good for you.
Where it lands — The message is a gift to whoever it reaches, and a choice for whoever hears it; God (﷾) judges each person justly.
Qur'an 2:256 — Surat al-Baqara (The Cow), verse 256
“Let there be no compulsion in religion: Truth stands out clear from Error: whoever rejects evil and believes in Allah hath grasped the most trustworthy hand-hold, that never breaks. And Allah heareth and knoweth all things.”
Cited for
Are you trying to convert me?
The response
No. I am making you aware of Islam, and we are just having a friendly discussion, not a debate. I cannot make anyone believe. The Qur'an tells even the Prophet (ﷺ) that he cannot guide everyone he loves, but God (﷾) guides whom He wills. It also says, "Let there be no compulsion in religion". So the choice is yours. Read, think and decide for yourself. If you decide Islam is not for you, I will say what the Qur'an teaches: "To you be your Way, and to me mine." Whatever you decide, I am still your friend.
Where it lands — The Muslim shares Islam in a friendly discussion and presses no one. The choice is the friend's, and if it is no, the friendship goes on.
Perspectives
What a friend may say: no evidence, no God
Some friends say they simply lack belief in God, and that the burden of proof lies on the believer. Others say science explains the world without God.
I see no evidence for God, so I simply lack belief. The burden of proof is on the one who believes.
Rebuttal
Not being persuaded is a report on one's own mind, not a claim about the world. But the question still stands: why is there anything at all? It always was, it simply is, it came from nothing, or a Creator made it. Each answer is a claim, and the honest course is to weigh them, not to set them all aside. The philosopher David Hume gave the rule for both sides: a wise man proportions his belief to the evidence.
Science explains the world, so there is no need for God.
Rebuttal
Science explains how things work, and does it superbly. But it explains one thing by another. It cannot say why there is anything at all, or what we are here for. The biologist Peter Medawar said science cannot answer how everything began, or what we are here for. And the rule that only science gives knowledge is not a finding of science: no laboratory found it.
The Islamic perspective
Invite with wisdom and gentleness, honestly and one point at a time. Start from reason and from what your friend accepts. Judge no one's heart, leave each person's fate to God (﷾), and leave the choice to your friend.
Muslims are told to invite with wisdom and beautiful preaching, and to argue in the best way.
Musa and Harun were told to speak mildly even to Pharaoh, so gentleness is owed to everyone invited.
God (﷾) loves gentleness in every matter, and the Prophet (ﷺ) was sent as a mercy, not to curse.
Every child is born upon the fitra. This is a teaching about all people, not a charge against anyone.
Only what is known to be true is used: no one may claim what he does not know.
There is no compulsion in religion; the Muslim conveys, and the choice is the listener's.