From What is a Jew? by Rabbi Maurice Kertzer, 1978.
BELIEF in the coming of the Messiah–a descendant of the House of David who would redeem mankind and establish a Kingdom of God on earth—has been part of the Jewish tradition since the days of the prophet Isaiah. As legend pictured him, the Messiah would be a human being of very special gifts; strong leadership, great wisdom and deep integrity. These he would use to stimulate a social revolution that would usher in an era of perfect peace. But there was never any suggestion of divine power brought to bear.
The Messiah was envisioned as a great leader, a moulder of men and society, was envisioned as a but, for all that, a human being, not a God. According to one tradition, the Messiah already has visited the world once, in the days of the First Temple. But his mission then was not crowned with success. For before the talents of the Messiah can be effective, men must be ready to establish a world of righteousness and human harmony. The second corning of the Messiah, it was held, was to be preceded by a generation of preparation. Before his arrival “his footsteps” would be heard, and men were to turn their hearts to God. For generations the corning of the Messiah was a literal truth to every Jew. Solomon Mainion, noted philosopher of the eighteenth century, wrote in his Autobiography that when he was a boy he always slept under a heavy quilt, with the covers well over his head. But before falling asleep he always made certain that one ear was exposed, so that if the Messiah chose that night to come down his street, he would not miss the joyous footsteps.
Today, only the extreme Orthodox still cling to the literal belief in the coming of a Messiah. In the modern city of Jerusalem, many such believers gather in their synagogues to pray for a Redeemer to return to Zion. Most Jews, however, have reinterpreted the age-old belief in a Messiah, not as an individual Redeemer, but as mankind collective, who by their own acts can usher in a Kingdom o Heaven. When humanity has reached a level of true enlightenment, kindliness and justice, that will be the day of the Messiah.