Sahih Bukhari Volume 5, Book 58, Hadith Number 139.

Narated By Anas bin Malik : Allah’s Apostle said, “There is no life except the life of the Hereafter; so, O Allah! Improve the state of the Ansar and the Muhajirun.” And Anas added that the Prophet also said, “O Allah! Forgive the Ansar.”