The Catechism tells us "'Pray as if everything depended on God and work as if everything depended on you.' Even when we have done our work, the food we receive is still a gift from our Father; it is good to ask him for it and to thank him, as Christian families do when saying grace at meals" (2834).
We ask God not just to supply us with our material needs, but also to give us the Bread of Life - to satisfy our spiritual hunger.
Our daily bread is that which is necessary for life - the food which keeps our bodies alive and the spiritual nourishment which helps our souls to live and grow.
For both we have to work. "God helps those who help themselves" - if we sit back and wait for all our material needs to be met, we'll never be rich in material goods. We need to earn our living, to work, at times to make sacrifices. And if we work hard, the rewards are often great - many of us have more than we need, and are able to share our bounty with those who have less than they need.
Similarly, if we sit back and wait for God to touch our lives without praying and seeking Him out, how can we expect to receive the spiritual riches we seek? By our selfless acts, our active prayer life, our spiritual reading, those moments of calm when we ask God to come into our hearts, our seeking of God in the world around us and in the greatest and least of our fellow human beings, our regular participation in the Eucharist, we receive spiritual nourishment. And it is in doing all these things that we become rich, not just today but every day and for all eternity.