When Was Salah Made Obligatory in Islam?

Salah (Prayer) was made obligatory (Fard) approximately one year before the Hijrah (migration), during the Night of Mi'raj (The Ascension). On that night, the beloved Prophet ﷺ ascended above the seven heavens and was blessed with a special, highly honored audience with Allah the Almighty. On that day, Allah Ta'ala made the five daily prayers obligatory upon the Muslims.

Mi'raj refers to the ascension of Prophet Muhammad ﷺ to the heavens and his miraculous meeting with Allah Ta'ala. It was during this meeting that Allah Subhanahu wa Ta'ala ordained the obligation of Salah (prayer) for the Ummah (community).

Afterward, Jibril (AS) taught Prophet Muhammad ﷺ the method of performing Salah. He first demonstrated the method of offering prayer at the beginning of its prescribed time and later at the end of its time. In this manner, we come to know the schedule and regulations of Salah through the Hadith.

Initially, Allah Ta'ala made Salah (prayer) obligatory fifty times a day; later, by His mercy, it was reduced to five times, but the reward remains equal to fifty times.
— [Sahih Al-Bukhari, Book of Mi'raj]

This means that Salah (prayer) is an act of worship that Allah Ta'ala made obligatory directly in the heavens, without any intermediary.