Reported by Ibn Maaja, the Prophet Mohammad (ﷺ) said that:
“The sin of the interest is seventy times more severe than committing adultery with (one’s own) mother.”

In the peace pact with the Christians of Najran, the Prophet Mohammad (ﷺ) had included a clause that the agreement will be null and void if they continued the interest in their dealings.

The tribe Bani Mugheera was known to have been involved in the interest deeply. After the conquest of Makkah Al-Mukarramah the Prophet Mohammad (ﷺ) nullified all their interests and wrote to the Governor of that region to wage a war against them if they continued the interest.

The Prophet Mohammad (ﷺ)’s uncle Abbas bin Abdul Mutallib was a leading money lender. The Prophet Mohammad forfeited all the interest of the days of Jahiliyya and announced that :
“I forfeit all the interest of my uncle Abbas”.