Tafsir of Al-Mutaffifeen 83:1

Increasing and decreasing in the Measure and Weight will be a Cause for Regret and Loss An-Nasa'i and Ibn Majah both recorded from Ibn Abbas that he said, "When the Prophet came to Al-Madinah, the people of Al-Madinah were the most terrible people in giving measurement (i.e., they used to cheat). Thus, Allah revealed,

ويل للمطففين

Woe to Al-Mutaffifin. After this, they began to give good measure.'' The meaning of the word Tatfif here is to be stingy with measurement and weight, either by increasing it if it is due from the others, or decreasing it if it is a debt. Thus, Allah explains that the Mutaffifin those whom He has promised loss and destruction, whom are meant by "Woe'' are