Question:

I heard from a rabbi that the year 6000 will be the last year, the year when Moshiach will arrive and usher in the redemption. I thought we do not know when the "last" year will be, so why this prediction?

Answer:

The Talmud tells us that this world, as we know it, will last for six thousand years, with the seventh millennium ushering in the cosmic Shabbat, the Messianic Era. Six days a week we work, and on the Shabbat we rest and enjoy the fruits of our labor; the same is true with millenniums.

However, it is certainly possible for Moshiach to come earlier. And we believe, hope, and pray each day that this is the day when Moshiach will come. This is also analogous to the weekly Shabbat, which we have the prerogative of ushering in early on Friday afternoon (click here for more on this topic).

So yes, we don't know exactly when Moshiach will come, but we do know that it will be before the year 6000. (Currently, as I write this response, we are in the year 5768 [2007-8].)

I would only like to add that the anticipation of Moshiach's arrival at any moment has considerably heightened in recent years in light of the pronouncement by the Lubavitcher Rebbe that Moshiach's arrival is very very imminent!