Sahih Bukhari Volume 008, Book 075, Hadith Number 394.

Narated By Ibn Umar : Whenever Allah's Apostle returned from a Ghazwa or Hajj or 'Umra, he used to say, "Allahu Akbar," three times; whenever he went up a high place, he used to say, "La ilaha illal-lahu wahdahu la sharika lahu, lahu-l-mulk wa lahu-l-hamd, wa huwa'ala kulli Shai 'in qadir. Ayibuna ta'ibuna 'abiduna lirabbina hamidun. Sadaqa-l-lahu wa'dahu, wa nasara'abdahu wa hazama-l-ahzaba wahdahu."