Mark 14:13
So he sent two of his disciples, telling them, go into the city, and a man carrying a jar of water will meet you. Follow him — the water-jar carrier is the distinctive sign: men carried water in wineskins; women carried it in jars. A man carrying a jar of water would be immediately noticeable and identifiable. The instruction to follow him without approaching first communicates the same pre-arranged signal as the colt-finding of chapter 11.