Hadith 1736
Sayyiduna Abu Hurairah (may Allah be pleased with him) narrates that the Prophet Muhammad (peace and blessings be upon him) said: "The angels of the night and the angels of the day come to you in succession. They gather together at the Fajr and Asr prayers. Then those angels who have spent the night among you ascend (to the heavens). Their Lord asks them, although He knows best about them, 'In what condition did you leave My servants?' They reply: 'We left them while they were praying, and when we came to them, they were also praying.'"