Why do we fast Ramadan?

Praise be to Allah, the Lord of the Worlds; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.

Know that initially the months are equal.  Ramadan is like Shawwal, like Muharram, like Rajab, …etc.

But Allah favored some months over others by what He prescribed in such months and the Blessings He bestowed on His slaves during such months.  So, Allah favored Ramadan over all other months.  He characterized it by fasting and by the revelation of the Qur'an.  Allah also made one of the nights of Ramadan better than 1000 months “The Night of Al Qadr”.

Indeed Allah has an Absolute Wisdom in everything He does.  Allah Says (interpretation of meaning): {And your Lord creates whatsoever He wills and chooses, ….}[28:68].

Allah knows best.