"The three shall spread their blackend wings and be the vengeful striking hammer of God” is the final line to The Duke’s prayer. Other than the fact that all three of the Saints wear black coats and turtle necks there is another relation to the story. When Connor jumps off the top of his building the robe he is wearing looks something like wings. The white robes that each of the brothers are wearing when they go into the police station becomes the black shirts that Rocco delivers. Their ‘wings’ become ‘blackened.’"

— Boondock symbolism (symbology ;D) explained on angelfire (via veritaaas)