Sahih Bukhari Volume 4, Book 52, Hadith Number 312.

Narated By Abu Uthman An-Nahdi : Mujashi (bin Mas’ud) took his brother Mujalid bin Musud to the Prophet and said, “This is Mujalid and he will give a pledge of allegiance to you for migration.” The Prophet said, “There is no migration after the Conquest of Mecca, but I will take his pledge of allegiance for Islam.”