Where is the Messiah right now? According to Sanhedrin 98a, he is sitting at the gates of Rome among the lepers.
Rabbi Yehoshua ben Levi asked Elijah the prophet: when will the Messiah come? Elijah said: "Go ask him yourself." Where is he? "At the entrance to Rome." How will I recognize him? "He sits among the poor who suffer from diseases. All of them untie and retie their bandages all at once. But the Messiah unties and reties them one at a time, because he thinks: perhaps I will be summoned, and I must not be delayed."
Rabbi Yehoshua ben Levi went to the Messiah and said: "Peace upon you, my master and teacher." The Messiah replied: "Peace upon you, son of Levi." He asked: "When will the master come?" The Messiah said: "Today."
Rabbi Yehoshua ben Levi returned to Elijah. "He lied to me," he said. "He told me 'today,' and he did not come." Elijah explained: he was quoting (Psalms 95:7)—"Today, if you would hear His voice." The Messiah comes today—if Israel is worthy.
The passage also records what signs will accompany the Messiah's approach. Rabbi Abba said: when Eretz Yisrael produces abundant fruit, the end is near, based on (Ezekiel 36:8). Rabbi Eliezer said: when there is no work and no peace, the end is near. Rabbi Hanina said: the son of David will not come until a fish is sought for a sick person and cannot be found.
Some Sages dreaded the Messiah's arrival. Ulla said: let him come after I am dead. Rabba said the same. The birth pangs of the Messianic era—the suffering that precedes redemption—were so feared that even great scholars preferred not to witness them. Only Rav Yosef was willing: "Let the Messiah come, and I will sit in the shadow of his donkey's excrement."