Sahih Muslim
The Book of Jihad and Expedition (Kitab Al-Jihad wal-Siyar)
Book Number: 019 / Hadith Number: 4343
It has been narrated on the authority of Auf b. Malik al-Ashja'i who said: I joined the expedition that marched under Zaid b. Haritha to Muta, and I received reinformcement from the Yemen. (After this introduction), the narrator narrated the tradition that had gone before except that in his version Auf was reported to have said (to Khalid): Khalid, didn't you know that the Messenger of Allah (way peace be upon him) had decided In favour of giving the booty (sized from an enemy) to one who killed him? He (Khalid) said: Yes. but I thought it was too much.