Sahih Muslim 649i
Abu Huraira reported Messenger of Allah ﷺ as saying: The servant is constantly in prayer so long as he is in a place of worship waiting for the prayer (to be observed in congregation), and the angels invoke (blessings upon him in these words): O Allah! pardon him. O Allah! show mercy to him, (and they continue to do so) till he returns (from the mosque having completed the prayer) or his ablution breaks. I said: How is the ablution broken? He said: By breaking of the wind noiselessly or with noise.
وَحَدَّثَنِي مُحَمَّدُ بْنُ حَاتِمٍ، حَدَّثَنَا بَهْزٌ، حَدَّثَنَا حَمَّادُ بْنُ سَلَمَةَ، عَنْ ثَابِتٍ، عَنْ أَبِي رَافِعٍ، عَنْ أَبِي هُرَيْرَةَ، أَنَّ رَسُولَ اللَّهِ ﷺ قَالَ " لاَ يَزَالُ الْعَبْدُ فِي صَلاَةٍ مَا كَانَ فِي مُصَلاَّهُ يَنْتَظِرُ الصَّلاَةَ وَتَقُولُ الْمَلاَئِكَةُ اللَّهُمَّ اغْفِرْ لَهُ اللَّهُمَّ ارْحَمْهُ . حَتَّى يَنْصَرِفَ أَوْ يُحْدِثَ " . قُلْتُ مَا يُحْدِثُ قَالَ يَفْسُو أَوْ يَضْرِطُ .