If they will not repent and thus become dependent on the final date, (The predetermined date for Mashiach’s coming) the Holy one, blessed be He, will set up a ruler over them, whose decrees shall be as cruel as Haman’s, thus causing Israel to repent, and thereby bringing them back to the right path.(1)
The context of this passage is that if Israel truly would repent on their own, the Messiah would come then. If Israel does not repent on their own then the original, predetermined date for Messiah to come would remain and God Himself would cause Israel to repent as a result of influence of the Holy Spirit along with great trials and tribulations, sometimes referred to as The Time Of Jacob's Trouble.
The coming ruler may be the Anti-Christ.
This Talmudic passage seems to fit perfectly with Zechariah 12:10 which states:
Learn more about the Zechariah 12:10 Messianic Prophecy.
1). Sanhedrin 97b.
Source: Mashiach: The Principle of Mashiach and the Messianic Era in Jewish Law and Tradition by Jacob Immanuel Schochet (New Expanded Edition) p.93