Surah Al-A'la 87:14
قَدْ أَفْلَحَ مَن تَزَكَّىٰ
He has certainly succeeded who purifies himself
Translation: Saheeh International
Tafsir
Successful winner indeed is he who purifies himself who cleanses himself by means of his adherence to faith
Excerpt from Tafsir al-Jalalayn, commentary on 87:14, via Quran.com. The reader has the full commentary and 9 more tafsirs.