Many of us take the prohibition of Riba lightly when in reality it is a major sin that we should not be involved in.
Sheikh Ibn Uthaymeen رحمه الله states in his Sharh al-Mumti alaa Zaad al-Mustaqni (own translation):
Riba is forbidden by the Quran, the Sunnah, the consensus of Muslims, and it is considered one of the major sins. Allah تعالى said: {But whoever returns – those are the companions of the Fire; they will abide eternally therein} [Al-Baqarah: 275], and said {O you who have believed, fear Allah and give up what remains of interest, if you should be believers.} {And if you do not, then be informed of a war from Allah and His Messenger} [Al-Baqarah: 278-279].
Furthermore, the Messenger ﷺ, cursed the one who consumes riba, the one who pays it, its two witnesses, and its scribe, and said: “They are all the same”. Therefore it is one of the greatest major sins. Sheikh Al-Islam (رحمه الله) mentioned in his book “إبطال التحليل” that what has come by way of warnings regarding Riba has not come for any other sin except Shirk and Kufr.