Sahih al-Bukhari — One-fifth of Booty to the Cause of Allah (Khumus) — Hadith No: 3142
Translation
Narrated Abu Qatada:We set out in the company of Allah's Messenger (ﷺ) on the day (of the battle) of Hunain. When we faced the enemy, the Muslims retreated and I saw a pagan throwing himself over a Muslim. I turned around and came upon him from behind and hit him on the shoulder with the sword He (i.e. the pagan) came towards me and seized me so violently that I felt as if it were death itself, but death overtook him and he released me. I followed `Umar bin Al Khattab and asked (him), "What is wrong with the people (fleeing)?" He replied, "This is the Will of Allah," After the people returned, the Prophet (ﷺ) sat and said, "Anyone who has killed an enemy and has a proof of that, will possess his spoils." I got up and said, "Who will be a witness for me?" and then sat down. The Prophet (ﷺ) again said, "Anyone who has killed an enemy and has proof of that, will possess his spoils." I (again) got up and said, "Who will be a witness for me?" and sat down. Then the Prophet (ﷺ) said the same for the third time. I again got up, and Allah's Messenger (ﷺ) said, "O Abu Qatada! What is your story?" Then I narrated the whole story to him. A man (got up and) said, "O Allah's Messenger (ﷺ)! He is speaking the truth, and the spoils of the killed man are with me. So please compensate him on my behalf." On that Abu Bakr As-Siddiq said, "No, by Allah, he (i.e. Allah's Messenger (ﷺ) ) will not agree to give you the spoils gained by one of Allah's Lions who fights on the behalf of Allah and His Apostle." The Prophet (ﷺ) said, "Abu Bakr has spoken the truth." So, Allah's Messenger (ﷺ) gave the spoils to me. I sold that armor (i.e. the spoils) and with its price I bought a garden at Bani Salima, and this was my first property which I gained after my conversion to Islam