Why we must celebrate the different biblical festivals?

The Plan of God Almighty
YHVH-Jehovah
Creator of the heavens and the earth

*Biblical festivals already fulfilled

Easter, Passover (Pesaj) , the unleavened breads (Hag HaMatzah), the first fruits (Bikkurim) and Pentecost (Shavuot) , teach us mainly about the most significant events of the first coming of the Messiah and the reason why the Events Are an important part of the divine redemption of man before YHVH Almighty God alone.

*Next Biblical festivals yet to be fulfilled

The  three last feasts, which are the Feast of Trumpets (Yom Teruah or Rosh HaShanah), the Day of Atonement (Yom Kippur) , and the Feast of Tents (Sukkot) At the Second Coming of the Messiah (Mashíaj).