Bread was the means of reconciliation after the Fall. Through the production of Bread, God taught mankind to trust in him, repent of sin, and walk with him in gratitude.
Bread is a partnership between Man and God. God is responsible for providing the seed, the soil, the sun, and the rain. We provide the planting, the harvesting, the grinding, and the baking.
Mankind's greatest temptation has always been to be like God, to be freed from his rule, to be dependent on no one but ourselves. Our first effort to be like God was to eat food that gave knowledge. Our last effort to be like God will be using knowledge to create food. In both cases, man ate food that God did not provide.