´It was narrated that Mutarrif said:` "Ash-Shabi was asked about the share of the Prophet and what he chose for himself. He said: 'The share of the Prophet was like the share of any Muslim man, and what he chose for himself was something precious; he chose whatever he wanted to."'
Explanation & Benefits
Hafiz Muhammad Ameen
(1) "Safi" refers to that special portion which the Imam or leader selects for himself before the distribution of war booty (mal-e-ghanimat), for example: a slave-girl, slave, camel, horse, etc.
(2) Thus, you (sallallahu alayhi wa sallam) had complete authority over the khums (one-fifth share). You could specially choose anything for yourself, just as you selected Safiyyah, Mother of the Believers (radi Allahu anha), from among the captives of Khaybar, freed her, and then married her.
(3) According to the evidences, the aforementioned narration is a sahih mursal (authentic mursal) narration.
Source: Sunan Nasa'i: Translation and Benefits by Shaykh Hafiz Muhammad Amin Hafizullah, Page: 4150