I AM THE BREAD OF LIFE
The background of this story and statement is the Exodus. While the Israelites were in the wilderness, God fed them with manna that fell from heaven. (Ex. 16) In other words, God sustained his people with it. Jesus performed a similar miracle, feeding 5,000 people from five barley loaves and two fish. But Jesus pointed out that manna was not the true bread from heaven. In fact, it was a type of the bread to come. Manna provided only temporary satisfaction and life. Jesus, in contrast, can satisfy us forever and give us eternal life. He gave his life so that we might have eternal life by receiving him in faith.
Jesus cautioned them, and us, against the pursuit of "food that perishes". (6:27) In other words, do not devote yourself to worldly things that pass away. Rather, seek food that endures to eternal life which the Son of Man will give to you. Again in other words, seek Christ and receive eternal life. What must you do to receive eternal life? Jesus answered the question. He said believe in him, Jesus, whom the Father has sent.
In the Lord's Supper, we take bread that reminds us that Jesus is the life giving bread from heaven. We need Christ to sustain our souls just like we need bread to sustain our bodies. As the Psalmist said, "Oh, taste and see that the LORD is good! Blessed is the man who takes refuge in him." (Ps. 34:8)