Sahih Bukhari Volume 004, Book 052, Hadith Number 317.
Hadith Section/Book: Sahih Bukhari Sahih Bukhari Book 52. Fighting for the Cause of Allah (Jihaad)
Narated By Abdullah : When the Prophet returned (from Jihad), he would say Takbir thrice and add, "We are returning, if Allah wishes, with repentance and worshipping and praising (our Lord) and prostrating ourselves before our Lord. Allah fulfilled His Promise and helped His Slave, and He Alone defeated the (infidel) clans."