What does Mark 14:22 mean?

Although the week-long Feast of Unleavened Bread doesn't start until the next evening, unleavened bread is still eaten on Passover. It represents the bread the Israelites ate on the eve of their escape from Egypt because they didn't have time to let bread rise (Exodus 12:8). It is necessary to "break" the bread because it is baked in a large, flat disk.

This is not the first time Jesus has compared Himself to bread that His followers must eat (John 6). Back in Capernaum, when confronted by a crowd after He miraculously fed thousands, Jesus accused them of merely wanting Him because He could make a few loaves of bread and a couple fish feed a crowd of thousands. He explained that He is the bread of life.

The symbolism has always been difficult to understand. When Jesus told the people that they needed to "eat the flesh of the Son of Man and drink his blood" (John 6:53), many of His followers abandoned Him (John 6:66). When the early church celebrated the Lord's Supper, eating the bread as Jesus' body, their pagan detractors accused them of cannibalism. Catholicism still teaches transubstantiation: that somehow the bread literally becomes Jesus' flesh and the wine His blood.

But Jesus is speaking in a metaphor (John 6:63). When God sent manna to the Israelites in the wilderness, it kept them alive for a time, but eventually they all died. Those who "eat" the bread of life will never die. We must intentionally allow Jesus to become part of us to receive eternal life. Obviously, our bodies die. But if we take the spiritual life Jesus offers, our spirits will live.