In John 6, Jesus compares himself to the manna that the Israelites received in the desert (see Exodus 16). Then he says that if anyone wants eternal life, they must eat his flesh and drink his blood.

Was Jesus proposing that his followers literally eat him? No.

But perhaps Jesus wanted his words to be shocking to get people's attention. Eating human flesh in a literal way would have been barbaric. But since Jesus' eternal life was somehow symbolized in his flesh and blood, which he would give as an atoning sacrifice for human sin, his followers needed to be willing to receive his sacrifice into themselves by faith in order to receive eternal life.

After Jesus died and rose from the dead, death had no hold on him anymore. And yet he surprised his disciples by showing them the marks from the wounds in his hands and side. It was as if Jesus was saying, "This is the cost of human sin." But with his hands outstretched and showing the marks of his crucifixion, he was also saying, "I love you this much."

When we come to the meal Jesus gave us, we receive his body and his blood in a symbolic way and in a spiritual way. The Holy Spirit connects us to the risen, flesh-and-blood Jesus in heaven, and we are connected anew with his once-for-all sacrifice for us.