Rejection of Christian and pagan theological claims

قُلْ إِن كَانَ لِلرَّحْمَـٰنِ وَلَدٌ فَأَنَا۠ أَوَّلُ ٱلْعَـٰبِدِينَ

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