A.T. Robertson Commentary 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;" — Mark 14:13 (ASV)

Two of his disciples (δυο των μαθητων αυτου). Luke 22:8 names them, Peter and John.

Bearing a pitcher of water (κεραμιον υδατος βασταζων). This item also in Luke, but not in Matthew.