Surah Al-Mutaffifin — Ayah 3 (83:3)
وَإِذَا كَالُوهُمۡ أَو وَّزَنُوهُمۡ يُخۡسِرُونَ ٣
English translation (Saheeh International)
But if they give by measure or by weight to them, they cause loss.
Brief commentary
But when they measure or weigh for people they reduce the measurement and weight. This was the practice of the people of Madinah at the time the Prophet (peace be on him) migrated to them.