Sayyiduna Ibn Abbas (may Allah be pleased with them both) said: When the Messenger of Allah (peace and blessings be upon him) passed by this verse: "And by the soul and Him who proportioned it, and inspired it with its wickedness and its righteousness" [Al-Shams: 8], he would pause, then say: "O Allah, grant my soul its righteousness (taqwa); You are its Guardian and its Master, and You are the best of those who purify it."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 11145