Sahih Bukhari Volume 005, Book 059, Hadith Number 516.
Hadith Section/Book: Sahih Bukhari Sahih Bukhari Book 59. Military Expeditions Led by the Prophet (PBUH) (Al-Maghaazi)
Narrated By Abu Musa Al-Ashari : When Allah's Apostle fought the battle of Khaibar, or when Allah's Apostle went towards it, (whenever) the people, (passed over a high place overlooking a valley, they raised their voices saying, "Allahu-Akbar! Allahu-Akbar! None has the right to be worshipped except Allah." On that Allah's Apostle said (to them), "Lower your voices, for you are not calling a deaf or an absent one, but you are calling a Hearer Who is near and is with you." I was behind the riding animal of Allah's Apostle and he heard me saying. "There Is neither might, nor power but with Allah," On that he said to me, "O Abdullah bin Qais!" I said, "Labbaik. O Allah's Apostle!" He said, "Shall I tell you a sentence which is one of the treasures of Paradise" I said, "Yes, O Allah's Apostle! Let my father and mother be sacrificed for your sake." He said, "It is: There is neither might nor power but with Allah."