Albert Barnes Commentary Mark 14:12-13

"And on the first day of unleavened bread, when they sacrificed the passover, his disciples say unto him, Where wilt thou that we go and make ready that thou mayest eat the passover? And he sendeth two of his disciples, and saith unto them, Go into the city, and there shall meet you a man bearing a pitcher of water: follow him;" — Mark 14:12-13 (ASV)

They killed the passover. The paschal lamb, which was slain in keeping the passover.

Go and prepare. Go and prepare a lamb, have it roasted, and properly prepared with the usual things to eat with it.

The city. The city of Jerusalem. They were now in Bethany, about two miles from the city.

A man bearing a pitcher of water. This could have been known only by the infinite knowledge of Christ. Such a thing could not have been conjectured, nor was there any prior arrangement between him and the man that he would be in a particular place at that time to meet them, for the disciples themselves proposed the inquiry.

If Jesus knew a circumstance like that, then he, in the same way, must have known all things. Then he sees all the actions of humankind, hears every word, and marks every thought. Then the righteous are under his care, and the wicked, much as they may wish to be unseen, cannot escape the notice of his eye.