Sahih al-Bukhari 659
Narrated Abu Huraira:
Allah's Messenger (ﷺ) said, "The angels keep on asking for Allah's Blessing and Forgiveness for anyone of 
you as long as he is at his Musalla (praying place) and does not do Hadath (passes wind). The angels 
say, 'O Allah! Forgive him and be Merciful to him.' Each one of you is in the prayer as long as he is 
waiting for the prayer and nothing but the prayer detains him from going to his family."
حَدَّثَنَا عَبْدُ اللَّهِ بْنُ مَسْلَمَةَ، عَنْ مَالِكٍ، عَنْ أَبِي الزِّنَادِ، عَنِ الأَعْرَجِ، عَنْ أَبِي هُرَيْرَةَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ ‏
"‏ الْمَلاَئِكَةُ تُصَلِّي عَلَى أَحَدِكُمْ مَا دَامَ فِي مُصَلاَّهُ مَا لَمْ يُحْدِثْ اللَّهُمَّ اغْفِرْ لَهُ، اللَّهُمَّ ارْحَمْهُ‏.‏ لاَ يَزَالُ أَحَدُكُمْ فِي صَلاَةٍ مَا دَامَتِ الصَّلاَةُ تَحْبِسُهُ، لاَ يَمْنَعُهُ أَنْ يَنْقَلِبَ إِلَى أَهْلِهِ إِلاَّ الصَّلاَةُ ‏"‏‏.‏