Angels come to you in shifts by night and by day. They meet at salaat al-fajr and salaat al-‘asr, then those who had stayed with you at night ascend, and are asked by the One Who knows better than they: ‘How did you find My servants?’ They say, We left them when they were praying, and we came to them when they were praying
Reported by al-Bukhaari, al-Fath, 2/33