Sahih Bukhari Volume 3, Book 27, Hadith Number 23.
Narated By ‘Abdullah bin ‘Umar : Whenever Allah’s Apostle returned from a Ghazwa, Hajj or ‘Umra, he used to say Takbir thrice at every elevation of the ground and then would say, “None has the right to be worshipped but Allah; He is One and has no partner. All the kingdoms is for Him, and all the praises are for Him, and He is Omnipotent. We are returning with repentance, worshipping, prostrating, and praising our Lord. He has kept up His promise and made His slave victorious, and He Alone defeated all the clans of (non-believers).”