Hadees Related to Slaves (Ghulam)

Abu Umamah Radiyallahu 'anhu narrates that Nabi Sallallahu 'alaihi wasallam returned from Khyber and with him were two slaves. So, 'Ali Radiyallahu 'anhu said: O Rasulallah! Grant us a servant. He replied: Take anyone you desire of the two. 'Ali said:
Choose for me. Rasulullah pointing to one said: Take him, but do not beat him; for I saw him offering Salat on our return from Khyber, and I have been forbidden to beat those who perform Salat. (Musnad
Alimad, Tabarani, Majma'uz-Zawaid)