The Women - 4:6
Test the orphans when they reach the age of marriage. If you see maturity in them, give them their property. Do not eat their wealth in extravagance and haste, lest they grow up. Let the rich give up (the wages of his efforts to protect the property). Let the poor spend an appropriate amount. Return their property to them in the presence of witnesses. Allah is sufficient as the Reckoner.
Warning:
The Women/4:10
Those who eat the property of orphans unjustly will fill their bellies with fire and will end up in Hell.