The Book Pertaining to the Remembrance of Allah, Supplication, Repentance and Seeking Forgiveness (Kitab Al-Dhikr)
Muslim :: Book 35 : Hadith 6532
Abu Musa Ash'ari reported that Allah's Messenger (may peace be upon him) said to him: Should I not direct you to the words from the treasures of Paradise, or he said: Like a treasure from the treasures of Paradise? I said: Of course, do that. Thereupon he said:" There is no might and no power but that of Allah."