The Cost of Discipleship is a Dietrich Bonhoeffer classic. In chapter fifteen, we find his interpretations on The Lord’s Prayer, including on the statement of Jesus: “Give us this day our daily bread”.

As long as the disciples are on earth, they should not be ashamed to pray for their bodily needs. He who created men on earth will keep and preserve their bodies. It is not that his creation should be despised. The disciples are told to ask for bread not only  for themselves but for all men on the earth, for all men are their brethren.

The disciples realize that while it is a fruit of the earth, bread really comes down from above as a gift of God alone. That is why they have to ask for it before they take it (166-167).