Narrated Ibn 'Abbas (R.A.) : The Prophet (S.A.W) narrating about his Lord (A.W) said, "Allah ordered (the appointed angels over you) that the good & the bad deeds be written, and he then showed (the way) how (to write). If somebody intends to do a good deed & he does not do it, then Allah will write for him a full good deed (in his account with Him); & if he intends to do a good deed & actually did it, then Allah will write for him (in his account) with Him (its reward equal) from 10 to 700 times, to many more times; & if somebody intended to do a bad deed & he does not do it, then Allah will write a full good deed (in his account) with Him, & if he intended to do it (a bad deed) & actually did it, then Allah will write 1 bad deed (in his account)."
Sahih <i>Al-Bukhari</i>, Vol.8, <i>Hadith</i> No. 498
From "The Noble Quran" (King Fahd Complex, S.A)
