وَقَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ : " الْمَلَائِكَةُ يَتَعَاقَبُونَ فِيكُمْ : مَلَائِكَةٌ بِاللَّيْلِ ، وَمَلَائِكَةٌ بِالنَّهَارِ " ، وَقَالَ : " يَجْتَمِعُونَ فِي صَلَاةِ الْفَجْرِ وَصَلَاةِ الْعَصْرِ ، ثُمَّ يَعْرُجُ إِلَيْهِ الَّذِينَ بَاتُوا فِيكُمْ ، فَيَسْأَلُهُمْ وَهُوَ أَعْلَمُ : كَيْفَ تَرَكْتُمْ عِبَادِي ؟ فَقَالُوا : تَرَكْنَاهُمْ وَهُمْ يُصَلُّونَ ، وَأَتَيْنَاهُمْ وَهُمْ يُصَلُّونَ " .
And the Prophet Muhammad (peace be upon him) said: There are some angels of Allah who come to you in succession; some of these angels come at night and some during the day. These angels gather at the times of Fajr (dawn) prayer and Asr (afternoon) prayer. Then those angels who have stayed among you ascend to the heavens. Although Allah knows everything, He asks them: In what condition did you leave My servants? They say: When we left them, they were praying, and when we came to them, they were praying as well.