Surah 43:81
"Say: ‘If the Merciful had a son, I (would be) the first of the ones who served (him)."
43.81 – If the Merciful had a son, I (would be) the first of the ones who served (him)
After reading many verses that declare emphatically that Allah does not and would not have a son, the reader may be surprised to encounter a verse that seems to still consider the possibility. Another verse that shares the subjunctive mood is 39.4: “If Allah wanted to take a son . . .” The verses following 43.81, however, seem to carry the sense of denial found in other passages about a “son of Allah.” See “Son of God in the Quran”.
- from The Quran with Christian Commentary: A Guide to Understanding the Scripture of Islam