أَلَمۡ تَرَ إِلَى ٱلَّذِينَ يُزَكُّونَ أَنفُسَهُمۚ بَلِ ٱللَّهُ يُزَكِّي مَن يَشَآءُ وَلَا يُظۡلَمُونَ فَتِيلًا ٤٩
Have you not seen those who claim themselves to be pure? Rather, Allāh purifies whom He wills, and injustice is not done to them, [even] as much as a thread [inside a date seed].
Translation: Saheeh International (English)
Each word's meaning and sound
Do you not know, O Messenger, the affair of those who are full of praise for themselves and of what they do? Allah alone praises whomever He wills, because He knows whatever is hidden in people’s hearts, and will not lessen the reward for their actions in any way, not even as much as the thread of a date stone.
Al-Mukhtasar in interpreting the Noble Quran