Catechism of the Catholic Church

God is the sovereign master of his plan. But to carry it out he also makes use of his creatures' cooperation. This use is not a sign of weakness, but rather a token of almighty God's greatness and goodness. For God grants his creatures not only their existence, but also the dignity of acting on their own, of being causes and principles for each other, and thus of cooperating in the accomplishment of his plan. (1884, 1951)