الزخرف — Az-Zukhruf Ayat 81

قُلْ اِنْ كَانَ لِلرَّحْمٰنِ وَلَدٌ ۖفَاَنَا۠ اَوَّلُ الْعٰبِدِيْنَ

Qul in kāna lir-raḥmāni walad(un), fa ana awwalul-‘ābidīn(a).

"Say, [O Muhammad], "If the Most Merciful had a son, then I would be the first of [his] worshippers.""