Rabbi Joshua ben Levi asks the prophet Elijah:
"When will the Messiah come?" he replied: "Go, ask him yourself."--"Where is he?"--"At the gates of Rome."--"How can I recognize him?"--"He is sitting between poor people laden with diseases; all the rest are unbinding all their wounds at the same time and binding them up again, but he is unbinding them one at a time and rebinding them, because he thinks: perhaps I will be needed, and there must be no delay." And this he [Rabbi Joshua] went to him and said: "Peace be with you, Lord and Master!" He replied: "Peace be with you, Son of Levi!" He asked: "When will the Master come?" and the other answered: "Today."
Then he returned to Elijah, who asked him: "What did he tell you?" He replied: "Peace be with you, son of Levi!" then he said: "He has promised to you and your father the world to come." But he responded: "He lied to me, because he said he would come today, and he did not come." Elijah replied: "This is what he meant: If today you would listen to his voice (Psalm 95:7)."
_(Babylonian Talmud, b. Sanh. 98a.)