Short answer
No. Having questions is not a sin, and neither is a passing doubt that you dislike. Some Companions once told the Prophet (ﷺ) they had thoughts too terrible to say. He called their distress "the faith manifest". He said Allah (﷾) forgives passing thoughts, if a person does not act on them or speak of them. What faith cannot rest on is a settled doubt about its core. That core is this: Allah (﷾) is God, Muhammad (ﷺ) is Allah's (﷾) Messenger, and the Qur'an is Allah's (﷾) word. So when a doubt comes, look into it and ask those who know. Certainty grows in steps. Even Abraham, who believed, asked to see how Allah (﷾) gives life, "just to reassure my heart".
Full explanation
A question is not a doubt
Many people call a question a doubt. They are not the same. A question is when you believe something, but want to understand it better. What does this verse mean? How do I answer this objection? A doubt is when you are no longer sure that it is true.
Questions are welcome in Islam. The Qur'an teaches the believer to pray: "O my Lord! advance me in knowledge" (20:114). The Companions asked the Prophet (ﷺ) hard questions. He once told them that each person's place in the next life is already written. They asked whether they should stop doing deeds. He did not scold them. He answered: keep doing deeds.
“High above all is Allah, the King, the Truth! Be not in haste with the Qur'an before its revelation to thee is completed, but say, "O my Lord! advance me in knowledge."”
Ali reports that at a funeral the Prophet (ﷺ) said every person's place in Paradise or the Fire has already been written. The Companions asked whether they should then rely on what was written and give up doing deeds. He said: keep doing deeds, for each person will find it easy to do the deeds that lead to where he was created for. He then recited Qur'an 92:5-7.
| Kind | What it is | Is it a sin? | What to do |
|---|---|---|---|
| A question | You believe, and want to understand | No | Ask people of knowledge |
| A passing whisper | A thought you dislike and push away | No | Seek refuge in Allah (﷾) and stop |
| A settled doubt about the core | No longer sure that it is true | Faith cannot rest on it | Look for the answer until you are sure |
A passing thought is not a sin
Some of the Companions came to the Prophet (ﷺ) troubled. They had thoughts that each of them felt were too grave to speak of. He asked whether they really found that. They said yes. He said: "That is the faith manifest." They hated the thought and pushed it away. That distress was a sign of faith, not of its loss.
He also said that Allah (﷾) forgives the evil thoughts that pass through the mind. That holds as long as a person does not act on them or speak of them. He warned that Satan would ask who created this and that, and in the end who created his Lord. When that comes, he said, seek refuge in Allah (﷾) and stop there. You are not your passing thoughts.
Abu Huraira reports that some of the Companions came to the Prophet (ﷺ) and said they found thoughts in their minds that each of them thought too grave to speak of. He asked whether they really found that. They said yes. He said: that is the faith manifest.
Abu Huraira reports that the Prophet (ﷺ) said Allah has forgiven his people the evil thoughts that pass through their minds, as long as they do not speak of them or act on them.
Abu Hurayra reports that the Prophet (ﷺ) said that Satan comes to a person and asks who created this thing and that, until he asks who created his Lord. When that thought comes, the person should seek refuge in Allah and stop there.
What faith rests on
Faith in Islam has six articles. They are belief in Allah (﷾), His angels, His books, His messengers, the Last Day and the decree. At its heart are three truths. Allah (﷾) is the one God. Muhammad (ﷺ) is Allah's (﷾) Messenger. The Qur'an is Allah's (﷾) word. The Prophet (ﷺ) said that whoever meets Allah (﷾) with no doubt about the first two will in the end enter Paradise. The Qur'an describes the believers as those who believed "and have never since doubted" (49:15). It opens by calling itself the Book in which there is "guidance sure, without doubt" (2:2).
So a settled doubt about these truths is not something to live with. It is something to resolve. A doubt that comes and that you fight against is different. That is part of the test, and the cure is to look for the answer. Feeling unsure for a while is not the same as rejecting Islam. Nor is not yet having an answer to an objection. Do not decide that you are lost. Keep looking.
Abu Huraira reports that on the march to Tabuk, when food ran short, the Prophet (ﷺ) prayed over what was left and it was more than enough. He then said: I bear witness that there is no god but Allah and that I am His messenger; the servant who meets Allah with these two, having no doubt about them, will enter Paradise.
“Only those are Believers who have believed in Allah and His Messenger, and have never since doubted, but have striven with their belongings and their persons in the Cause of Allah: Such are the sincere ones.”
“This is the Book; in it is guidance sure, without doubt, to those who fear Allah;”
Umar ibn al-Khattab reports that a stranger in very white clothes, with no sign of travel on him, sat before the Prophet (ﷺ) and asked him about Islam, faith and excellence in worship. Asked about faith, the Prophet said it is to believe in Allah, His angels, His books, His messengers and the Last Day, and to believe in the divine decree, its good and its evil. Afterwards the Prophet told Umar the stranger was Gabriel, who had come to teach them their religion.
Certainty comes in steps
The Qur'an speaks of certainty in more than one degree. It speaks of knowing "with certainty of mind", and then of seeing "with certainty of sight" (102:5-7). Those verses speak of the Fire, but they show that certainty has degrees. The Qur'an also calls its own message the "Truth of assured certainty" (69:51). So being sure is not one fixed point. It can grow.
Think of a fire. You can be sure it is there because someone you trust tells you. Then you see it with your own eyes. You were sure before, and now you are surer still. A Muslim must have the first: a mind that is sure. Some things will be seen only in the next life.
“Nay, were ye to know with certainty of mind, (ye would beware!) Ye shall certainly see Hell-Fire! Again, ye shall see it with certainty of sight!”
“But verily it is Truth of assured certainty.”
Certainty of mind
You are sure, because the reasons are clear (102:5).
Certainty of sight
You see it with your own eyes (102:7).
Even prophets asked to see
Abraham said: "Show me, Lord, how You will raise the dead." Allah (﷾) asked: "Have you no faith?" He said: "Yes, but just to reassure my heart" (2:260). So he was not in doubt. He already believed, and he asked to see as well. Allah (﷾) showed him, with four birds brought back to life.
Moses, who spoke with Allah (﷾), asked: "O my Lord! show (Thyself) to me, that I may look upon thee." Allah (﷾) said: "By no means canst thou see Me (direct)." When His glory touched the mountain, it crumbled to dust (7:143). So asking for more certainty is not a lack of faith. But not everything will be shown in this life.
“When Abraham said: "Show me, Lord, how You will raise the dead, " He replied: "Have you no faith?" He said "Yes, but just to reassure my heart." Allah said, "Take four birds, draw them to you, and cut their bodies to pieces. Scatter them over the mountain-tops, then call them back. They will come swiftly to you. Know that Allah is Mighty, Wise."”
“When Moses came to the place appointed by Us, and his Lord addressed him, He said: "O my Lord! show (Thyself) to me, that I may look upon thee." Allah said: "By no means canst thou see Me (direct); But look upon the mount; if it abide in its place, then shalt thou see Me." When his Lord manifested His glory on the Mount, He made it as dust. And Moses fell down in a swoon. When he recovered his senses he said: "Glory be to Thee! to Thee I turn in repentance, and I am the first to believe."”
What to do when a doubt comes
First, ask what kind it is. If it is a whisper, such as asking who created your Lord, seek refuge in Allah (﷾) and stop there. If it is a real question, look into it. Ask people of knowledge, and read the reasons. The Qur'an invites this. It asks its readers to look for contradictions in it. It says they would find many if it were not from Allah (﷾) (4:82).
Do not carry it alone, and do not give up your prayer while you look. If such thoughts will not leave you and weigh on you every day, talk to a doctor as well. Help for this is real.
Abu Hurayra reports that the Prophet (ﷺ) said that Satan comes to a person and asks who created this thing and that, until he asks who created his Lord. When that thought comes, the person should seek refuge in Allah and stop there.
“Do they not consider the Qur'an (with care)? Had it been from other Than Allah, they would surely have found therein Much discrepancy.”
Perspectives
Religion forbids doubt
Some critics of religion say that believers are told never to doubt, so that they never examine their faith.
Religions forbid doubt so that believers never look closely at what they believe.
Rebuttal
Islam welcomes questions, and teaches the prayer for more knowledge (20:114). It tells those who make claims about God (﷾) to bring their proof (2:111). It blames those who follow their fathers without thinking. It asks for certainty as the end of a search, not instead of one. Passing doubts are forgiven, and distress at them is called a sign of faith.
The Islamic perspective
Questions are welcome, and passing thoughts are forgiven. Faith rests on being sure of its core truths, and certainty grows in steps. When a doubt comes, a Muslim seeks refuge from whispers and looks for the answer to real questions.
The Prophet (ﷺ) called the Companions' distress at thoughts too grave to speak "the faith manifest".
Allah (﷾) forgives passing evil thoughts, if a person does not act on them or speak of them.
The believers are those who believed and have never since doubted.
The Qur'an speaks of certainty of mind, certainty of sight and the truth of certainty.
Abraham believed, and asked to see how Allah (﷾) raises the dead, to reassure his heart.