Silsilat al-Ahadith al-Sahihah

Sayyiduna Bara’ bin ‘Azib (may Allah be pleased with him) narrates that the Messenger of Allah (peace and blessings be upon him) said: “Usury has seventy degrees, the least of which (in sin) is equivalent to a man committing adultery with his own mother.” And the greatest usury, that is, excess, is that a person violates the honor of his brother.”