Calvin on Work and Prayer

In the Institutes Calvin elaborates on the Lord's Prayer. He explains why we have to pray for our daily bread even though we have good jobs and can provide for ourselves.

When we ask God to give us, the meaning is, that the thing asked is simply and freely the gift of God, whatever be the quarter from which it comes to us, even when it seems to have been specially prepared by our own art and industry, and procured by our hands, since it is to his blessing alone that all our labors owe their success.

(Institutes, Book III, Chapter XX, Paragraph 44).