The Messenger of Allah ﷺ said: Anyone amongst you who sat in a place of worship waiting for the prayer is in prayer and his ablution is not broken, the angels invoke blessing upon him (in these words): O Allah! pardon him. O Allah! have mercy upon him.

أَنَّ رَسُولَ اللَّهِ ﷺ قَالَ أَحَدُكُمْ مَا قَعَدَ يَنْتَظِرُ الصَّلاَةَ فِي صَلاَةٍ مَا لَمْ يُحْدِثْ تَدْعُو لَهُ الْمَلاَئِكَةُ اللَّهُمَّ اغْفِرْ لَهُ اللَّهُمَّ ارْحَمْهُ