Ya'qub bin Ibrahim bin Sa'd يعقوب بن إبراهيم بن سعد بن إبراهيم · The Book of Salah

"They distracted us from Salatul-Wusta (the middle prayer) until the sun went down."

"Angels come to you in succession by night and day, and they meet at Fajr prayer and 'Asr prayer. Then those who spent the night among you ascend, and He (Allah) will ask them, although He knows best: 'In what condition did you leave My slaves.' They will say: 'We left them when they were praying and we came to them when they were praying.'"