Ibn Abbas reported: The Messenger of Allah, peace and blessings be upon him, said
Verily, Allah has recorded good and bad deeds and He made them clear. Whoever intends to perform a good deed but does not do it, then Allah will record it as a complete good deed. If he intends to do it and does so, then Allah the Exalted will record it as ten good deeds up to seven hundred times as much or even more. If he intends to do a bad deed and does not do it, then Allah will record for him one complete good deed. If he does it then Allah will record for him a single bad deed.
Source: Sahih Bukhari 6126