When we study and celebrate the Old Testament Feasts we are not looking back to something that God did in the past. We are actually looking into the future and anticipating what God promised that He would do during the time we are living now.
As Christians we believe that the celebration of the feasts were pointing to a greater fulfillment. We believe that the Feast of Passover was fulfilled with Christ as our Paschal Lamb (1 Peter 1:17-21). We also believe that the outpouring of the Holy Spirit that we read about in Acts 2 is the fulfillment of the Feast of Pentecost.
What about the Feast of Tabernacles? We are still anticipating the fulfillment of the Feast of Tabernacles. After the people of Israel left Egypt God introduced Himself to His people. He told Moses to prepare the Israelites for the moment when He would manifest His presence on Mount Sinai. So it came about on the third day, when it was morning, that there were thunder and lightning flashes and a thick cloud upon the mountain and a very loud trumpet sound, so that all the people who were in the camp trembled. And Moses brought the people out of the camp to meet God, and they stood at the foot of the mountain (Exodus 19:16–17). God introduced Himself with the sound of trumpets; the Hebrew word for trumpet is SHOFAR.
In Leviticus 23:24 Moses told the people of Israel to keep the Feast of Trumpets as a rest and reminder of the first time that they heard the sound of the Shofar. When we celebrate the Feast of Trumpets we are anticipating the fulfillment of God coming and introducing Himself to the world again. When we blow the trumpets we are by faith proclaiming and preparing for the moment that the Lord will once again introduce Himself to His people.
Suggested scripture reading:
Numbers 29:1
Exodus 19:9, 16-20
Exodus 20:18
1 Corinthians 15:50-53
Matthew 24:31