91:9
قَدْ أَفْلَحَ مَن زَكَّىٰهَا
qad aflaḥa man zakkāhā
The one who purifies his soul succeeds
Indeed he succeeds who purifies his ownself (i.e. obeys and performs all that Allâh ordered, by following the true Faith of Islâmic Monotheism and by doing righteous good deeds).