Belief

Narrated Abu Huraira (Radi-Allahu 'anhu):

Allah's Apostle (Sallallahu 'Alaihi Wa Sallam) said, "If any one of you
improve (follows strictly) his Islamic religion then his good deeds will be
rewarded ten times to seven hundred times for each good deed and a bad deed
will be recorded as it is."

Bukhari Vol. 1 : No. 40