Prohibition of exploitation and oppression

إِنَّ ٱلَّذِينَ يَأْكُلُونَ أَمْوَٰلَ ٱلْيَتَـٰمَىٰ ظُلْمًا إِنَّمَا يَأْكُلُونَ فِى بُطُونِهِمْ نَارًا ۖ وَسَيَصْلَوْنَ سَعِيرًا

Indeed, those who devour the property of orphans unjustly are only consuming into their bellies fire. And they will be burned in a Blaze [i.e., Hellfire].