Mark 14:13

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.

These two disciples were Peter and John (Luke 22:8), and here is evident the fact that Mark never mentioned Peter any more than was necessary, a reticence which must be traced to Peter himself, and which also explains the apostolic modesty also evidenced in the gospel of John.

Bearing a pitcher of water ... That this pitcher of water was in some way connected with the observance of the passover meal, and that the man bearing it was doing so in such a connection is unreasonable. If indeed there was such a "pitcher carrying" in connection with the passover meal, there would have been thousands of others doing the same thing, and such a "sign" would have been useless. Those who find here a proof that this was Passover find what is not in it.