Surah Az-Zukhruf, Verse 81
قُلْ إِن كَانَ لِلرَّحْمَٰنِ وَلَدٌۭ فَأَنَا۠ أَوَّلُ ٱلْعَٰبِدِينَ
Translation — Sahih International
Say, [O Muhammad], "If the Most Merciful had a son, then I would be the first of [his] worshippers."
Source
Kur'an-ı Kerim, Zuhruf Suresi 43:81
https://kuran.diyanet.gov.tr/mushaf/kuran-meal-2/43-suresi-81-ayet