Surah Al Mutaffifin Tafseer

And when they have to give by measure or weight to (other) men, give less than due.

He says in another Ayah,

وَأَوْفُوا الْكَيْلَ إِذا كِلْتُمْ وَزِنُواْ بِالقِسْطَاسِ الْمُسْتَقِيمِ ذَلِكَ خَيْرٌ وَأَحْسَنُ تَأْوِيلً

And give full measure when you measure, and weigh with a balance that is straight. That is good and better in the end. (17:35)

Allah also says,

وَأَوْفُواْ الْكَيْلَ وَالْمِيزَانَ بِالْقِسْطِ لَا نُكَلِّفُ نَفْسًا إِلاَّ وُسْعَهَا

And give full measure and full weight with justice. We burden not any person, but with that which he can bear. (6:152)

and He says,

وَأَقِيمُواْ الْوَزْنَ بِالْقِسْطِ وَلَا تُخْسِرُواْ الْمِيزَانَ

And observe the weight with equity and do not make the balance deficient. (55:9)

Allah destroyed the people of Shu`ayb and wiped them out because of their cheating in weights and measurements.

Threatening the Mutaffifin with standing before the Lord of all that exists

Then Allah says as a threat to them,

أَلَا يَظُنُّ أُولَيِكَ أَنَّهُم مَّبْعُوثُونَ