Sahih Muslim Book 12, Hadith Number 3951.

Chapter : Disapproval of buying the donated property by the donor himself.

This hadith has been narrated on the authority of Zaid b. Aslam with the same chain of transmitters but with this (change) that the hadith transmitted on the authority of Malik and Rauh (he was the son of Qisirn) is more complete and lengthy.