2:179There is life for you in retaliation, O people of understanding, so that you may refrain.

2:275Those who swallow usury will not rise, except as someone driven mad by Satan's touch. That is because they say, “Commerce is like usury.” But God has permitted commerce, and has forbidden usury. Whoever, on receiving advice from his Lord, refrains, may keep his past earnings, and his case rests with God. But whoever resumes—these are the dwellers of the Fire, wherein they will abide forever.