The Book of Sacrifices (Kitab Al-Adahi)
Muslim :: Book 22 : Hadith 4849
Rafi' b. Khadij reported that he said: Allah's Messenger, we are going to encounter the enemy tomorrow. and we do not have large knives with us. The rest of the hadith is the same, but no mention is made of this:" The people hastened and they boiled (flesh) in the earthen pots. He (the Holy Prophet), cammanded and these were turned over and the narrator narrated the whole event.