I hope you studied Islam.
2:185 It was the month of Ramadan in which the Qur’an was bestowed from on high as a guidance unto man and a self-evident proof of that guidance, and as the standard by which to discern the true from the false. **So, whoever of you lives to see this month shall fast throughout it.
**The Quran told the reason that because Quran is revealed at once in this month on worldly sky, we should fast as thanksgiving in it.
In other place of Quran it’s mentioned that Muslims should celebrate the revealing of Quran (I forgot the reference).