Oaths and Vows

Bukhari :: Book 8 :: Volume 78 :: Hadith 673

Narrated Abu Huraira:

Allah's Apostle said, "(Following are) two words (sentences or utterances that are very easy for the tongue to say, and very heavy in the balance (of reward,) and the must beloved to the Gracious Almighty (And they are): Subhan Allah wa bi-hamdihi; Subhan Allahi-l-'Azim,"