The Cow - 2:275
"Those who eat usurious money rise up like one who is struck by the devil. This is because they say, "Usury is like shopping". But Allah has made shopping lawful and usury unlawful. And whoever receives a reminder from his Lord and desists, he may keep what he has earned in the past, and his affair is up to Allah. As for those who continue, they are the inhabitants of Hell, and they will abide therein forever."
Those who earn unjustly may spend or eat this income, provided that they repent, do not repeat it and use it for good deeds:
The Table Spread/5:91
Satan wishes to put enmity and hatred between you by intoxicants and gambling and to keep you from the remembrance of Allah and from prayer. Are you not giving up now?
The Table Spread/5:93
Those who believe and do righteous deeds, there is no sin on them for what they eat, as long as they believe and do righteous deeds in obedience to the commandments, and they abstain from sin and believe, and they abstain and do good. Allah loves those who do good.