كتاب المساجد
Read the English translation first, with the original Arabic directly underneath.
It was narrated from Abu Hurairah that the Messenger of Allah (ﷺ) said:
"The angels send Salah upon any one of you so long as he is in the place where he prays, and so long as he does not invalidate his ablution, (saying): 'O Allah, forgive him, O Allah, have mercy on him.'"
إِنَّ الْمَلاَئِكَةَ تُصَلِّي عَلَى أَحَدِكُمْ مَا دَامَ فِي مُصَلاَّهُ الَّذِي صَلَّى فِيهِ مَا لَمْ يُحْدِثِ اللَّهُمَّ اغْفِرْ لَهُ اللَّهُمَّ ارْحَمْهُ