The Fajr and 'Asr prayers in a group in the mosque
Abu Hurayra, may Allah be pleased with him, said that the Messenger of Allah, may Allah bless him and grant him peace, said:
"There are angels who take turns in being with you in the night and other angels in the day, and they meet together at the prayers of Fajr and 'Asr. Then the ones who were with you during the night ascend and Allah asks them although He knows better than they do 'How were My slaves when you left them?" They say, 'When we left them they were praying and when we came to them, they were praying."
Al-Bukhari, Muslim, an-Nasa'i and Ibn Khuzayma related it.
About his words, "There are angels who take turns in being with you," Ibn Hajar said, "It is said that they are the guardian angels. Al-Qurtubi said, 'I think that the most evident view is that it is other than them. This view is strengthened by the fact that it is not transmitted that the guardian angels ever leave the slave nor that the guardian angels of the night are not the same as the guardian angels of the day."
'Iyad said, "The wisdom of them meeting at these two prayers is part of Allah's kindness to His slaves and His generosity to them since He made the angels meet at a time when His slaves are in a state of obedience so that they can give the best testimony on their behalf."
Ibn Hajar said in the Fath "The hadith contains an indication of the immense importance of these two prayers since the two groups meet during them while there is only one group present
during the other prayers. This indicates the nobility of the two times mentioned. It is related that provision is allocated after the Subh prayer and that actions ascend at the end of the day. So who- ever is engaged in an act of obedience at that time is blessed both in his provision and in his actions, and Allah knows best. It also shows that this community is honoured above others and means therefore that its Prophet is honoured above all other Prophets. It informs us of the love of Allah's angels for us so that our love for them is increased and we draw near to Allah by that. There are other salutory lessons, and Allah knows them best."