The prohibition of interest (Riba) was declared in 8th Hijri. This happened after the conquest of Makkah.

Allah revealed clear verses in Surah Al-Baqarah (2:275–279) that strictly forbade all forms of interest. These verses were among the final rulings of Islamic Shariah revealed to the Prophet Muhammad (PBUH).

The Prophet (PBUH) also gave his last sermon (Khutbah Hujjat-ul-Wida) in which he clearly declared that all interest transactions from the time of ignorance (Jahiliyyah) were cancelled, starting with the interest owed to his uncle, Hazrat Abbas (R.A).

This made it clear that taking or giving interest is strictly haram (forbidden) in Islam. It was one of the last major economic reforms made in Islamic law.

The year 8 Hijri marked a significant milestone in Islamic financial ethics by officially banning Riba.