The Date of the Obligation of Fasting

Question:
When did fasting first become obligatory, O Shaykh?

Answer:
Fasting became obligatory in the second year after the migration of the Messenger of Allah (peace and blessings be upon him)?
So the Messenger of Allah (peace and blessings be upon him) fasted nine Ramadans, because the duration of his mission (peace and blessings be upon him) was twenty-three years, of which thirteen years were in Makkah before the migration. He commanded the oneness of Allah and singling Him out for worship, and he forbade shirk (associating partners with Allah), establishing the creed.
When the creed was established and the Prophet (peace and blessings be upon him) migrated to al-Madinah, the obligatory acts were revealed to him. The prayer is the second pillar; it was made obligatory upon him in Makkah on the night of the Ascension, shortly before the migration, and he (peace and blessings be upon him) prayed it in Makkah. As for fasting and zakah (the obligatory alms), they were made obligatory in the second year of the migration. Yes.