Verse 49

أَلَمْ تَرَ إِلَى ٱلَّذِينَ يُزَكُّونَ أَنفُسَهُم بَلِ ٱللَّهُ يُزَكِّى مَن يَشَآءُ وَلَا يُظْلَمُونَ فَتِيلًا

Have you observed those who are trying to cleanse themselves? However, God cleanses whomever He wills and without the least injustice.