Sahih Bukhari Volume 5, Book 59, Hadith Number 490.

Narrated By Anas bin Malik : Regarding Allah’s Statement: “Verily! We have granted you (O, Muhammad) Manifest victory.” (48.1) It refers to the Al-Hudaibiya Pledge. And the companions of the Prophet said (to the Prophet), “Congratulations and happiness for you; but what reward shall we get?” So Allah revealed: “That He may admit the believing men and women to gardens beneath which rivers flow.” (48.5)