I wrote a letter to Nafiʿ and Nafiʿ wrote in reply to my letter that the Prophet ﷺ had suddenly attacked Bani Mustaliq without warning while they were heedless and their cattle were being watered at the places of water. Their fighting men were killed and their women and children were taken as captives; the Prophet ﷺ got Juwairiya on that day. Nafiʿ said that Ibn ʿUmar had told him the above narration and that Ibn ʿUmar was in that army.  

أَنَّ النَّبِيَّ ﷺ أَغَارَ عَلَى بَنِي الْمُصْطَلِقِ وَهُمْ غَارُّونَ وَأَنْعَامُهُمْ تُسْقَى عَلَى الْمَاءِ فَقَتَلَ مُقَاتِلَتَهُمْ وَسَبَى ذَرَارِيَّهُمْ وَأَصَابَ يَوْمَئِذٍ جُوَيْرِيَةَ حَدَّثَنِي بِهِ عَبْدُ اللَّهِ بْنُ عُمَرَ وَكَانَ فِي ذَلِكَ الْجَيْشِ