Quran on Riba
Whatever Ribā (increased amount) you give, so that it may increase in the wealth of the people, it does not increase with Allah; and whatever Zakāh you give, seeking Allah’s pleasure with it, (it is multiplied by Allah, and) it is such people who multiply (their wealth in real terms)
and for their charging Ribā (usury or interest) while they were forbidden from it, and for their devouring of the properties of the people by false means. We have prepared, for the disbelievers among them, a painful punishment.
O ye who believe! Devour not usury, doubled and multiplied; but fear Allah; that ye may (really) prosper.
Those who take ribā (usury or interest) will not stand but as stands the one whom the demon has driven crazy by his touch. That is because they have said: “Sale is but like ribā.’’, while Allah has permitted sale, and prohibited ribā. So, whoever receives an advice from his Lord and desists (from indulging in ribā), then what has passed is allowed for him, and his matter is up to Allah. As for the ones who revert back, those are the people of Fire. There they will remain forever.
Allah destroys ribā and nourishes charities, and Allah does not like any sinful disbeliever.
O you who believe, fear Allah and give up what still remains of ribā, if you are believers.
But if you do not (give it up), then listen to the declaration of war from Allah and His Messenger. However, If you repent, yours is your principal. Neither wrong, nor be wronged.