Surah Al-Isra — Ayah 35 (17:35)
وَأَوۡفُواْ ٱلۡكَيۡلَ إِذَا كِلۡتُمۡ وَزِنُواْ بِٱلۡقِسۡطَاسِ ٱلۡمُسۡتَقِيمِۚ ذَٰلِكَ خَيۡرٞ وَأَحۡسَنُ تَأۡوِيلٗا ٣٥
English translation (Saheeh International)
And give full measure when you measure, and weigh with an even [i.e., honest] balance. That is the best [way] and best in result.
Brief commentary
Give full measure when you measure for others and do not cheat them. Weigh with an accurate scale that does not diminish or undervalue anything. That giving of full weight and measure is better for you in this world and the Hearafter, than giving short measure or weight.