Which is worse: fornication, drinking alcohol, or usury?

The gravest sins are usury, then adultery, then drinking alcohol.

The one who consumes usury has been warned by Allah of war, and the Messenger of Allah, peace and blessings be upon him, cursed him. A single dirham of usury is worse than thirty-six acts of adultery.

Adultery has never been permissible. Its punishment in this world is greater than that for alcohol, and its harms are more severe.

Alcohol was initially permissible, and its prescribed punishment (ḥadd) is less, and its harms are less than those of adultery, even though it is considered the mother of all evils.