Abu Dhar (Ra) narrates that Rasúlullãh (saw) said: Should I not inform you of the words dearest to Allãh? I said: O Rasúlullãh! Do tell me about the words dearest to Allãh. He said: To Allãh the dearest words are Subhanallãhi wabihamdihi (Glory be to Allãh who is above all faults, and all praise be to Him).
(Muslim)

Another narration says, the dearest words to Allãh are: Subhana Rabbi wabihamdihi (Glory be to my Rabb who is above all faults, and all praise be to Him).
(Tirmidhí)