He meant Judas, the son of Simon Iscariot, who was about to betray him, though he was one of the Twelve.

One of the disciples, Judas Iscariot, who was about to betray Jesus, asked:

The Devil had already put the thought of betraying Jesus into the mind of Judas Iscariot, the son of Simon;

"It is the one," answered Jesus, "to whom I shall give a piece of bread after dipping it in the dish." And, when Jesus had dipped the bread, he took it and gave it to Judas, the son of Simon Iscariot;

"What has happened, Master," said Judas (not Judas Iscariot), "that you are going to reveal yourself to us, and not to the world?"