Surah An-Nisa — Ayah 2 (4:2)
وَءَاتُواْ ٱلۡيَتَٰمَىٰٓ أَمۡوَٰلَهُمۡۖ وَلَا تَتَبَدَّلُواْ ٱلۡخَبِيثَ بِٱلطَّيِّبِۖ وَلَا تَأۡكُلُوٓاْ أَمۡوَٰلَهُمۡ إِلَىٰٓ أَمۡوَٰلِكُمۡۚ إِنَّهُۥ كَانَ حُوبٗا كَبِيرٗا ٢
English translation (Saheeh International)
And give to the orphans their properties and do not substitute the defective [of your own] for the good [of theirs]. And do not consume their properties into your own. Indeed, that is ever a great sin.
Brief commentary
Guardians, give orphans (whose fathers have died and who have not yet reached maturity) their wealth in full when they come of age and have sound judgement. Do not exchange what is permitted for what is prohibited: taking what is good and valuable from the property of the orphans and replacing it with something bad and of little worth from your own property. Also, do not take the property of the orphans and combine it with your own wealth – that is a great crime before Allah.