What is communion?

1 Corinthians 11:23-26I [Paul] pass on to you what I received from the Lord himself. On the night when he was betrayed, the Lord Jesus took some bread and gave thanks to God for it. Then he broke it in pieces and said, “This is my body, which is given for you. Do this in remembrance of me.” In the same way, he took the cup of wine after supper, saying, “This cup is the new covenant between God and his people—an agreement confirmed with my blood. Do this in remembrance of me as often as you drink it.” For every time you eat this bread and drink this cup, you are announcing the Lord’s death until he comes again.

Communion is both an expression and demonstration of your faith in Jesus Christ. The bread symbolizes Christ’s body, which was broken for you during his crucifixion. Jesus took the punishment for your sins by dying on the cross. The cup of wine or juice symbolizes Christ’s blood, which he shed for you as he died on that cross. Christ’s death was necessary for you to be saved from your sins through faith in him. When you take communion, you are demonstrating symbolically your appreciation for Christ’s death, and you are remembering what he went through so that you could be free from sin.