Surah Al-Mutaffifin 83:3

وَإِذَا كَالُوهُمْ أَو وَّزَنُوهُمْ يُخْسِرُونَ

But if they give by measure or by weight to them, they cause loss.

Translation: Saheeh International

Tafsir

but who when they measure for them or weigh for them they cause them loss they diminish for them the measure or the weight.

Excerpt from Tafsir al-Jalalayn, commentary on 83:3, via Quran.com. The reader has the full commentary and 9 more tafsirs.