Nahj al-Balāgha
Hadith 576اللَّهُمْ إِنّي أَوَّلُ مَنْ أَنابَ، وَسَمِعَ وَأَجَابَ، لَمْ يَسْبِقْنِي إِلاَّ رَسُولُ اللهِ (صلى الله عليه وآله) بِالصَّلاَةِ.
O my Allāh! I am the first who leaned (towards Thee) and who heard and responded (to the call of Islam). No one preceded me in prayer (ṣalāt) except the Prophet.