The Messenger of Allah (ﷺ) said, "There are angels who take turns in visiting you by night and by day, and they all assemble at the dawn (Fajr) and the afternoon ('Asr) prayers. Those who have spent the night with you, ascend to the heaven and their Rubb, Who knows better about them, asks: 'In what condition did you leave My slaves?' They reply: 'We left them while they were performing Salat and we went to them while they were performing Salat."'

[Al-Bukhari and Muslim].