The God we worship is the God of all mercy. Scripture tells us repeatedly that His mercies crown all that He does, and one aspect of this mercy is that He gives “food to all flesh: for his mercy endureth for ever” (Ps. 136:25).
One central aspect of His great mercy is His provision of food. And, at the center of this, we find His provision of spiritual food. Man needs more nourishment than can be provided by the food that perishes. We are invited by God to eat and to drink everlasting life. As with everything else we do on the spiritual plane, we use physical instruments.
When you sing spiritual songs, you do so with a physical throat, mouth, and tongue. When you offer spiritual worship to God, you do so by offering your physical body. When the Jews in the wilderness ate and drank spiritual food and drink, they did so by eating and drinking what God provided for them on the physical plane. And it is the same with us. This wine and bread here is as physical as anything else in the room. It is not ethereal. The wine came from a vineyard, and the bread from a wheat field.
When I say the words of institution, these elements do not become ghostly. They are not spiritual in that way. When we eat and drink this way, we are partaking of Christ spiritually because we are coming to Him in obedience, and God inhabits the obedience of His people. This obedience, contra many, does not make the spiritual physical, but rather makes the physical spiritual. So come, eat and drink.