I wrote to Nafi' inquiring from him whether it was necessary to extend (to the disbelievers) an invitation to accept (Islam) before meeting them in fight. He wrote (in reply) to me that it was necessary in the early days of Islam. The Messenger of Allah (ﷺ) made a raid upon Banu Mustaliq while they were unaware and their cattle were having a drink at the water. He killed those who fought and imprisoned others. On that very day, he captured Juwairiya bint al-Harith. Nafi' said that this tradition was related to him by Abdullah b. Umar who (himself) was among the raiding troops.