Short answer
Islam points to three kinds of evidence: the universe could not have made itself (52:35), its order and design point to a wise Maker, and every person is born with an inner sense of God (fitrah). Revelation and the prophets' miracles confirm this. The Quran invites you to reflect, not to believe blindly.
Knowing Allah is the first duty of every accountable person. In Maturidi creed, followed by Hanafis, a sane adult must recognise the Creator by reason from creation itself, even before a prophet's message reaches him. Ash'aris tie that duty to revelation, though both agree reason points to Allah.
The four schools agree on this.
Explanation
Nothing comes from nothing. The Quran asks: "Or were they created by nothing, or were they the creators of themselves? Or did they create the heavens and the earth?" (52:35-36). Everything in the world has a beginning and depends on something else. Sunni theologians argued that a chain of dependent things must end in a Being who depends on nothing and has no beginning. That Being is Allah.
Order and design. "Indeed, in the creation of the heavens and the earth and the alternation of the night and the day are signs for those of understanding" (3:190). The precise laws of nature, the balance that lets life exist, and the complexity of a single cell all point to knowledge and will, not chance. The Quran adds that if there were several gods, the heavens and earth would have fallen into ruin (21:22).
The fitrah. Allah created people with an inborn sense of Him (30:30). The Prophet ﷺ said every child is born on the fitrah, and then surroundings shape him. This is why people across history and cultures turn to a higher power, especially in moments of danger.
Revelation. The Quran itself, its challenge and its preservation, and the truthful lives of the prophets confirm what reason already suggests. Imam Abu Hanifa taught that no one has an excuse for not knowing his Creator, given what he sees of the heavens and the earth. If questions still trouble you, read Who created Allah? and Who is Allah?
The evidence
Quran, Surah At-Tur 52:35-36
أَمْ خُلِقُوا۟ مِنْ غَيْرِ شَىْءٍ أَمْ هُمُ ٱلْخَٰلِقُونَ ﴿٣٥﴾ أَمْ خَلَقُوا۟ ٱلسَّمَٰوَٰتِ وَٱلْأَرْضَ ۚ بَل لَّا يُوقِنُونَ ﴿٣٦﴾
Or were they created by nothing, or were they the creators [of themselves]? Or did they create the heavens and the earth? Rather, they are not certain.
Argues that creation cannot come from nothing or make itself.
Quran, Surah Aal-i-Imraan 3:190
إِنَّ فِى خَلْقِ ٱلسَّمَٰوَٰتِ وَٱلْأَرْضِ وَٱخْتِلَٰفِ ٱلَّيْلِ وَٱلنَّهَارِ لَءَايَٰتٍۢ لِّأُو۟لِى ٱلْأَلْبَٰبِ ﴿١٩٠﴾
Indeed, in the creation of the heavens and the earth and the alternation of the night and the day are signs for those of understanding.
Calls people to reflect on creation as evidence.
Quran, Surah Ar-Room 30:30
فَأَقِمْ وَجْهَكَ لِلدِّينِ حَنِيفًۭا ۚ فِطْرَتَ ٱللَّهِ ٱلَّتِى فَطَرَ ٱلنَّاسَ عَلَيْهَا ۚ لَا تَبْدِيلَ لِخَلْقِ ٱللَّهِ ۚ ذَٰلِكَ ٱلدِّينُ ٱلْقَيِّمُ وَلَٰكِنَّ أَكْثَرَ ٱلنَّاسِ لَا يَعْلَمُونَ ﴿٣٠﴾
So direct your face toward the religion, inclining to truth. [Adhere to] the fitrah of Allah upon which He has created [all] people. No change should there be in the creation of Allah. That is the correct religion, but most of the people do not know.
People are created with an inborn sense of Allah.
Sahih al-Bukhari 1385
Sahih... كل مولود يولد على الفطرة فأبواه يهودانه أو ينصرانه ...
"Every child is born on the fitrah, then his parents make him a Jew, a Christian or a Magian."
Shows that belief in the Creator is natural to people.
Where the ruling is recorded
- al-Musayara (Ibn al-Humam), Section on knowing Allah by reason. Sets out the Hanafi Maturidi view that reason obliges knowing the Creator.
- Sharh al-Aqa'id al-Nasafiyya (al-Taftazani), Section on the world being originated (huduth al-alam). Gives the classical proof that the world had a beginning and needs a Maker.
Checked by our team. For a more accurate answer to your own situation, consult a scholar. Quran translation by Sahih International. Hadith Arabic from the standard editions of the six books and the Muwatta, with gradings as recorded there; the English is our own rendering. Spotted a mistake? Tell us.