God chose man-made products to represent something that man could not do for himself. Bread and wine are modest when compared to Solomon’s daily menu, yet bread and wine are too elaborate to be found in the world unprocessed.
Joe Rigney writes about this in chapter 7 of his book, The Things of Earth.
God mediates grace to us through created goods that have been cultivated and transformed by human effort. Bread is grain, but transfigured. Wine is grapes, but glorified. Human creativity and labor mingle with the stuff of God’s creation, and then God establishes the result as the church’s sacramental meal. (147)
God gave man grain and grapes, but men took those and developed more complex carbohydrates. This is the work of image-bearing, and God ratified the cultural advance by using bread and wine to honor the body and blood of His Son.
We can say that God gave us bread, but He gave it through agricultural and culinary discoveries. God continues to give to us through farmers and cooks. God also gave wine to gladden the heart of man, but no wineskin or bottle dropped from heaven. Other than the miracle in Cana, God has men plant and pick and press and wait. Communion, then, is a cultured meal.
Communion is also a meal that creates culture. This Table teaches us the way of love, of giving, of sacrifice. It also reminds us to depend on God and one another who share Christ’s body. The bread strengthens us and the cup gladdens our hearts, by faith, through earthly means that God ordained. Here the fruit of the field and the kitchen remind us of the fruit of the cross. Here is the seed that the Spirit will grow into more cultured fruit.