In our Gospel reading for the Palm Sunday procession, Jesus sends his disciples into Jerusalem to prepare for his triumphal entry. They are told to untether a donkey, and if there is any protest from the owner, they are to say simply, “The Master has need of it.” Strictly speaking, God has need of nothing, since he is the unconditioned act of existence. God doesn’t need our praise or our good works or anything. But this phrase signals the wonderful truth that God allows us to cooperate with his grace so that we can participate in the work that he wants to do. He gives us what Aquinas called “the dignity of causality.” We are privileged to be instruments in his hands.
Bishop Barron’s Sunday Sermons - Catholic Preaching and Homilies