This is how you are to eat it: with your loins girt, sandals on your feet and your staff in hand, you will eat it in a hurry. It is the LORD’s Passover. (Exodus 12:11)
To receive Holy Communion is to eat the Passover of the Lord; it is to eat his having been handed over to his suffering and death, the passion which--and this is the whole mystery and good news of Christianity--becomes the passing over of humanity from its self-imposed alienation into the Presence of the Father.
The mystery reveals itself as a pilgrimage. We eat the Passover as those in flight, those fleeing the captivity of sin. But the Promised Land is not the next stop. Our next stop after Holy Communion is the desert, the journey in which, through our homelessness, we begin to see more clearly the real problem of our rootlessness. We complain, we murmur, in our being tested we succumb to putting God to the test, and yet we are also fed miraculously and experience God healing the misery we have insisted upon for ourselves with our sins.