Passover begins Monday night this year. Passover is the night when Christ sat down with his disciples, His last supper with them. It's the night He prayed in the Garden of Gethsemane. The night He was arrested so that the next morning He could become our Passover Lamb, our Deliverer, our Redeemer. While the hundreds of thousands of passover lambs were being sacrificed at the temple altar, He hung on that cross so that He could free us from sin. It is appropriate that the Jewish people also call Passover the Festival of Freedom. God used the Exodus from Egypt to paint a type and picture, a representation of what Christ would become for us, a shadow of our Messiah. Just as He brought His people out of Egypt (Mitzrayim is the Hebrew word for Egypt, and means bondage, sin, the world system), He clothed Himself in humanity and set us free from sin.
He was the unleavened bread (leaven represents sin). The Feast of Unleavened Bread begins on Passover and lasts for seven days. During that seven days we do not eat anything with leaven in it. (Ex. 12 & 13; Deut. 16) At the same time, we ask God to search our hearts, to help us purge ourselves and deliver us from the leaven in our lives.
That year Passover started a little later in the week (although the sequence of events and timing, particularly whether He was crucified on Aviv 14 or Aviv 15, is hotly debated in messianic circles). Jesus was crucified at the same time as the morning lambs were sacrificed. He died at 3:00, the same time as the afternoon lambs were sacrificed. And He was buried just before sunset. He was in the ground three nights and three days, and He rose at the end of the Sabbath, just as the sun was going down to begin the first day of the week and the Festival of First Fruits (which is always on the Sunday after Passover begins, or as the Bible puts it, the day after the Sabbath following the first day of Passover). He was the First Fruits of the Father, risen from the grave and presented as a wave offering. Coincidentally, this year Easter falls on First Fruits.
Isn't God awesome? He delivers His people from physical bondage. Then He delivers His people from spiritual bondage on the same day, a couple thousand years later. He created a "moed," an appointed time, that we are to celebrate every year for the rest of eternity (Ex. 12:14; 1 Cor. 5:7-8). This is a commandment from God to His People. If we were supposed to celebrate it, to commemorate it every year, how much more so should we be celebrating these appointed meetings with God now that Christ's death, burial, and resurrection have brought double meaning to them?