Oneness, Uniqueness of Allah (Tawheed)

Bukhari :: Book 9 :: Volume 93 :: Hadith 484

Narrated Abu Musa:

We were with the Prophet on a journey, and whenever we ascended a high place, we used to say, "Allahu Akbar." The Prophet said, "Don't trouble yourselves too much! You are not calling a deaf or an absent person, but you are calling One Who Hears, Sees, and is very near." Then he came to me while I was saying in my heart, "La hawla wala quwwatta illa billah (There is neither might nor power but with Allah)." He said, to me, "O 'Abdullah bin Qais! Say, 'La hawla wala quwwata illa billah (There is neither might nor power but with Allah), for it is one of the treasures of Paradise." Or said, "Shall I tell you of it?"