Theophylact of Ohrid — as excerpted in the Catena Aurea on Mark 14:12-16

“He sends two of His disciples, that is, Peter and John, as Luke says, to a man unknown to Him, implying by this that He might, if He had pleased, have avoided His Passion. For what could not He work in other men, who influenced the mind of a person unknown to Him, so that he received them? He also gives them a sign how they were to know the house, when He adds, And there shall meet you a man bearing a pitcher of water.”