Pray as though everything depended on God. Work as though everything depended on you.
Augustine of Hippo (354-430) Christian church father, philosopher, saint [b. Aurelius Augustinus]
(Attributed)
Also attributed to St. Ignatius Loyola, St. Benedict, and Brigham Young. Attributed to Francis Cardnial Spellman (though it predates him).Variant: "Work as if everything depends on you, and pray as if everything depends on God."