Summary: Because of Jesus’ death on the cross and resurrection from the tomb, eternal life is available to all who receive of Jesus Christ.
In the Old Testament, there was a time that was called “Passover”. Much of the symbols we have with our Communion come from that time of celebration.
In the Passover meal, the bread had a particular significance. When the Hebrew women made their household bread, they took a piece of fermented dough they saved from a previous day and mixed it into their fresh flour. With time, the yeast would overtake the dough and she could then make her family’s daily bread. (After saving a piece for future baking, of course.) When God delivered the children of Israel out of Egyptian bondage, there wasn’t time to bake bread or hassle with yeast. They ate their bread unleavened.
Eating unleavened bread became a reminder of the time when God delivered the children of Israel out of bondage.
In Exodus 13:8-9, God gives meaning to the unleavened bread, He said, "And you shall tell your son on that day, saying, ’It is because of what the Lord did for me when I came out of Egypt.’  "And it shall serve as a sign to you …that the law of the Lord may be in your mouth; for with a powerful hand the Lord brought you out of Egypt."
At the Lord’s Supper, the bread that celebrated the people’s deliverance from Egyptian bondage took on a new meaning. Now it commemorates Jesus’ broken body and celebrates the Christian’s deliverance from the bondage of sin. Because of Jesus’ death on the cross and resurrection from the tomb, eternal life is available to all who receive of Jesus Christ.
Take and eat the bread.
When Jesus handed the cup to the disciples, at the first Communion, they naturally would have thought of the blood of the lamb smeared on the doorpost of their ancestors’ homes in Egypt. This was done in preparation for the tenth plague, God instructed the children of Israel to put the blood of the Passover lamb on the two doorposts and on the lentel of the house.
God had made a covenant with the people: when the death angel saw the blood on the doorposts, it would "pass over" that house.
But if a house did not have the blood on the doorposts and lentel, the death angel would visit their home and kill their first born son.
The Lord said in Exodus 12:13
"And the blood shall be a sign for you on the houses where you live; and when I see the blood I will pass over you, and no plague will befall you to destroy you when I strike the land of Egypt."
As the disciples drank the wine, they remembered the blood covenant. But Jesus reinterpreted the wine to symbolize a new covenant.
In the Lord’s Supper, Jesus’ blood now symbolizes more then salvation from a single night of terror, instead, it celebrates eternal salvation.
In 1 Peter 1:18-19 "knowing that you were not redeemed with perishable things like silver or gold from your futile way of life inherited from your forefathers,  but with precious blood, as of a lamb unblemished and spotless, the blood of Christ."
Today, we celebrate the Lord’s Supper with Christ.
As we partake of the fruit of the vine, we celebrate eternal salvation.