‘Amir Al Sha’bi said “The Prophet (ﷺ) had a special portion in the booty called safi. This would be a slave if he desired or a slave girl if he desired or a horse if he desired. He would choose it before taking out the fifth.”
Sunan Abi Dawud Book 20, Hadith 64
← Previous Hadith Mujja'ah went to the Prophet (ﷺ) asking him for the blood-money of his brother whom Banu Sadus from Banu Dhuhl had killed.

The Prophet (ﷺ) said: Had I appointed blood-money for a polytheist, I should have appointed it for your brother. But I shall give you compensation for him. So the Prophet (ﷺ) wrote (a document) for him that he should be given a hundred camels which were to be acquired from the fifth taken from the polytheists of Banu Dhuhl. So he took a part of them, for Banu Dhuhl embraced Islam.

He then asked AbuBakr for them later on, and brought to him the document of the Prophet (ﷺ). So AbuBakr wrote for him that he should be given one thousand two hundred sa's from the sadaqah of al-Yamamah; four thousand (sa's) of wheat, four thousand (sa's) of barley, and four thousand (sa's) of dates.

The text of the document written by the Prophet (ﷺ) for Mujja'ah was as follows: "In the name of Allah, the Beneficent, the Merciful. This document is from Muhammad, the Prophet, to Mujja'ah ibn Mirarah of Banu Sulma. I have given him one hundred camels from the first fifth acquired from the polytheist of Banu Dhuhl as a compensation for his brother."

Sunan Abi Dawud Book 20, Hadith 63 Next Hadith → Ibn ‘Awn said “I asked Muhammad about the portion of the prophet(ﷺ) and safi. He replied “A portion was taken for him along with the Muslims, even if he did not attend (the battle) and safi (special portion) was taken from the fifth before everything.”

Sunan Abi Dawud Book 20, Hadith 65