In this verse in the Quran, Allah makes it clear that Jesus (Isa) was not son of God.
It befits not (the Majesty of) Allah that He should beget a son [this refers to the claim of Christians against Allah, by saying that Isa (Jesus) is the son of Allah]. Glorified (and Exalted be He above all that they associate with Him). When He decrees a thing, He only says to it, “Be!” and it is.
Quran (Surah Maryam, Verse 35)