Many people think that the dates on which Easter and Passover are celebrated each year are the same, are connected, or are holidays of two different cultures celebrated in the spring of the year. They are connected. The connection is not that one appears first and the other happens so many days afterward. The connection is that the event which we celebrate called Easter happened during Passover nearly two thousand years ago.
Passover is always celebrated on the first full moon of spring. After the end of a cold winter, one would see the first signs of spring; budding trees, blooming flowers, or beginning shoots. The next full moon would be the day of Passover.
What is Passover? This is the celebration of the liberation of Israel from bondage in Egypt by sending the tenth plague. Any house, which had been marked by the blood from the sacrificial lamb, was passed over by death (Exodus 12:3-7,12-13,23). Jesus Christ was the Passover Lamb of God. As the blood of the sacrificed lamb caused death to bypass their homes, the blood of Jesus was shed for those who received His death in their place.
The next feast after Passover is that of the Unleavened Bread. Since Jesus Christ was without sin, He is the same as the unleavened bread. Many times in the Bible, leaven, or yeast, is representative of sin. So, in preparation for Passover, the woman of the house goes through the house and removes all of the yeast from it. During the Passover meal, all of the bread used is without yeast. This bread is matzo. It is striped, pierced, and without yeast. It is pure. It was, and is, a representative of Jesus Christ. This matzo, the middle one of three, is broken, buried, and resurrected. The Gospel of the Christ was within an ancient ceremony practiced by the Jews.
The third feast closely tied to the Passover and the Feast of Unleavened Bread is the Feast of First Fruits (Lev 23:10-11). This feast was for Israel to acknowledge the fertility of the land God gave them. To be very frank about this, this is what Easter has turned out to be. Easter is a derivative of the name of the Babylonian Goddess of fertility, Ishtar.
But the interesting thing about this feast is that it was to be celebrated on the first day of the week following Passover. This day would be Sunday. The first fruit that should be celebrated by Christians is the resurrection of Jesus Christ.
The other Biblical feasts of Israel also point toward the life, purpose, and ministry of Jesus Christ. But, the three aforementioned feasts that begin with Passover are more than a coincidental merging of two cultures. Where one ends, the other begins.