Short answer
No one created God (﷾). The argument for God (﷾) never says that everything needs a maker. It says that whatever depends on something else needs something to depend on. A being that depends on nothing needs no cause. Picture a man waiting for a loan, where each lender must first borrow from the next. If no one in the line has the money, he is never paid, however long the line is. Someone must have it without borrowing. To ask who lent money to that person misreads the case. A god who had a maker would not be God, and his maker would face the same question. The Prophet (ﷺ) foresaw this whisper. He told believers to seek refuge in Allah (﷾) from it and stop, because the question has no answer. Islam's answer is Allah (﷾), who needs nothing, while everything else needs Him.
Full explanation
Only what depends needs a cause
A thing is contingent when it depends on something else and might never have existed. Everything we see is like that. People exist because their parents met. They stay alive by air, food and the sun. The sun burns only while its fuel lasts. Each thing has its existence on loan. A chain of borrowed things cannot explain itself, however long it is. An endless line of carriages still needs an engine that pulls without being pulled. Ibn Sina, a Muslim philosopher of the eleventh century, drew this conclusion. There must be a being that depends on nothing and needs nothing.
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.
Everything we see depends on something else: its existence is on loan.
Can a long enough chain explain itself?
No. A line of borrowers never pays the loan unless someone has the money without borrowing.
So what must exist?
A being that depends on nothing and needs nothing.
Who made that being?
No one. A god with a maker would not be God, and his maker would face the same question.
Allah (﷾) needs nothing, and everything else needs Him.
A god with a maker would not be God
Suppose God (﷾) did have a maker. Then that maker would be the real God (﷾). The same question would be asked of him, and of his maker in turn. Either the line ends in a being that was never made, or it never ends and nothing is ever explained. The only answer that ends the question is a being that was never made. That is what the word God means. The Qur'an says He begets not, nor is He begotten, and there is none like Him.
“Say: He is Allah, the One and Only; Allah, the Eternal, Absolute; He begetteth not, nor is He begotten; And there is none like unto Him.”
One God (﷾), who needs nothing
Ibn Sina argued that a being that depends on nothing is not put together from parts. A thing put together from parts depends on them. So the universe itself cannot be that being. It is made of parts, and each part exists on loan. And there can be only one such being. Two beings that each needed nothing would have to differ in something. Whatever made them differ would be a part or a limit. The Qur'an says that people need Allah (﷾) and that He needs nothing. It calls Him al-Samad, the one all others need. It calls Him the First and the Last.
“O ye men! It is ye that have need of Allah: but Allah is the One Free of all wants, worthy of all praise.”
“Say: He is Allah, the One and Only; Allah, the Eternal, Absolute; He begetteth not, nor is He begotten; And there is none like unto Him.”
“He is the First and the Last, the Evident and the Immanent: and He has full knowledge of all things.”
“All that is on earth will perish: But will abide (for ever) the Face of thy Lord,- full of Majesty, Bounty and Honour.”
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.
The whisper the Prophet (ﷺ) foresaw
The Prophet (ﷺ) said that Satan would bring this very question. Satan would move from "who created this?" to "who created your Lord?" The Prophet (ﷺ) told the believer to seek refuge in Allah (﷾) and stop. That is not a refusal to think. The question has no answer because it asks for the maker of the one being that was never made.
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.
The same point in the Bible
Paul was a Christian missionary of the first century. He told the philosophers of Athens that God (﷾) is not worshipped with men's hands, as though He needed anything. God (﷾) gives life and breath to all. The Bible and the Qur'an agree on this point.
“God that made the world and all things therein, seeing that he is Lord of heaven and earth, dwelleth not in temples made with hands; Neither is worshipped with men’s hands, as though he needed any thing, seeing he giveth to all life, and breath, and all things;”
The objections answered
Hartle and Hawking, Physical Review D (1983)
Proposes the "no-boundary" state of the universe, a model in which time has no first edge. It is a proposal, not an established result.
Cited for
Some physicists propose models in which the universe has no first moment. One is the no-boundary proposal of Hartle and Hawking. Unbelievers argue that a universe with no first moment needs no cause.
The response
This argument, from things that depend on others, does not need a first moment. Suppose the past has no first edge, or goes back for ever. Every part of the universe still exists on loan. The question still stands: why does this universe exist at all? Ibn Sina himself held that the world had no beginning, and al-Ghazali rejected that view. Even so, Ibn Sina's argument led him to one necessary being, which means a being that depends on nothing. And none of these no-beginning models is proven.
Where it lands — Islam holds that the world was created and had a beginning. But even an endless chain would be borrowed existence, and it would point to the One who needs nothing.
Qur'an 57:3 — Surat al-Hadid (The Iron), verse 3
“He is the First and the Last, the Evident and the Immanent: and He has full knowledge of all things.”
Cited for
If God is beyond time and space, how can He know or act within time?
The response
The Qur'an answers with a question: "Should He not know,- He that created?" (67:14). The One who made all things knows all that happens in them. "Not a leaf doth fall but with His knowledge" (6:59). He is the First and the Last (57:3). The Prophet (ﷺ) praised Him as the First, with nothing before Him, and the Last, with nothing after Him (Muslim 2713). A maker need not live inside what he makes in order to know it or shape it. An author knows every page of his book, and writes each event in its place, yet he is on none of its pages. How He knows and acts is not like us, for there is nothing like Him (42:11). Not knowing how He does it is no reason to doubt that He does.
Where it lands — The Maker knows and rules all that He made. How He does so is His alone, and nothing is like Him.
Perspectives
Buddhist
Buddhism needs no Creator. The round of rebirth has no known beginning, and all things are impermanent and not-self, so there is no eternal, unchanging God.
The round of rebirth has no known beginning, so nothing needs a first cause.
Rebuttal
A chain with no first link explains nothing, because every link borrows its being from the one before. And the Buddha himself speaks of something that needs no cause. It is the unconditioned, in which no arising, no vanishing and no change is found.
All conditions are impermanent and all things are not-self, so there can be no eternal, unchanging God.
Rebuttal
The Buddha says the unconditioned has no arising, no vanishing and no change. So Buddhism itself holds that what is unconditioned is not impermanent and was never made. That is what Islam says of God (﷾): He is the First and the Last, He was not begotten, and nothing is like Him.
Then the universe needs no cause either
Bertrand Russell put the objection in 1927. If anything can exist without a cause, he said, it may as well be the world as God.
If God can exist without a cause, the universe can too, and we can stop there.
Rebuttal
Only what depends needs a cause. The universe is made of parts and has a beginning, so it depends. A being that depends on nothing has no parts and no beginning, and that is not a description of the universe.
Jain: the world was never created
Jainism teaches that the world was never created and will never perish. Jain teachers argued against a Creator: why would a perfect being want to create, and where would the material come from?
The world has no beginning and no end, and those who say it was created do not know the truth.
Rebuttal
A world with no beginning would mean an endless past already crossed to reach today, which can never be done. And modern cosmology finds that a universe that has on average been expanding has an edge in its past.
A perfect Creator would have no reason to create, and no material to make the world from.
Rebuttal
Islam does not say God (﷾) created out of need: people need Him, and He needs nothing. Nor did He need material beside Him. He is the originator of the heavens and the earth, and when He decrees a matter He says to it "Be," and it is. A maker who needed raw material would not be God, so this argument answers a god Islam also rejects.
The Islamic perspective
God (﷾) is the one being who depends on nothing, so He has no cause. Everything else holds its existence on loan from Him. The Prophet (ﷺ) told believers that the question "who created God?" is a whisper to be refused.
Only what depends on something else needs a cause. A being that depends on nothing needs none.
An endless chain of dependent things still needs a being outside it that depends on nothing. An endless line of borrowers is never a lender.
A being that depends on nothing can only be one. Two such beings would have to differ by a part or a limit.
A god who had a maker would not be God, and his maker would face the same question without end.
The Qur'an says people need Allah (﷾), and Allah (﷾) needs nothing. It calls Him the First and the Last.
The Prophet Muhammad (ﷺ) warned that Satan prompts the question "who created your Lord?" He told believers to seek refuge in Allah (﷾) from it.
God (﷾) is al-Samad, the Self-Sufficient on whom all depend, who begets not and is not begotten.
The Bible also says that God (﷾) needs nothing and gives life and breath to all.