Sahih Muslim Book 37, Hadith Number 6610.
Chapter : Exhortation for repentance.
Abu Huraira reported Allah’s Messenger (may peace be upon him) as saying: Allah, the Exalted and Glorious, said: I live in the thought of My servant and I am with him as he remembers Me. (The Holy Prophet) further said: By Allah, Allah is more pleased with the repentance of His servant than what one of you would do on finding the lost camel in the waterless desert. When he draws near Me by the span of his hand. I draw near him by the length of a cubit and when he draws near Me by the length of a cubit. I draw near him by the length of a fathom and when he draws near Me walking I draw close to him hurriedly.