Allaah سُبحانه وتعالى stated:
“The one who purified his soul is indeed
successful and the one who corrupts his soul is indeed destroyed.”
The meaning: The one who
magnifies his soul, lifts it and makes it superior by way of being
obedient to Allaah is indeed successful. And the one who makes his soul
inferior and insignificant and belittled it by way of disobedience to Allaah is
indeed the loser. There is nothing that belittles the soul like disobedience to
Allaah. And there’s nothing that magnifies the soul, makes it honorable and
raises it up (in status) like obedience to Him.
(Al-Jawaab Al-Kaafi pg.52)