Surah Ali 'Imran 3:67

مَا كَانَ إِبْرَٰهِيمُ يَهُودِيًّا وَلَا نَصْرَانِيًّا وَلَـٰكِن كَانَ حَنِيفًا مُّسْلِمًا وَمَا كَانَ مِنَ ٱلْمُشْرِكِينَ

Abraham was neither a Jew nor a Christian, but he was one inclining toward truth, a Muslim [submitting to Allāh]. And he was not of the polytheists.

Translation: Saheeh International

Tafsir

God in order to dissociate Abraham from their claims said No; Abraham in truth was not a Jew neither a Christian but he was a Muslim professing the Oneness of God and a hanīf who inclined away from all other religions towards the upright one; and he was never of the idolaters.

Excerpt from Tafsir al-Jalalayn, commentary on 3:67, via Quran.com. The reader has the full commentary and 9 more tafsirs.