The day that the Antichrist signs the peace treaty with Israel is the day that the period of time that has become known as "The Tribulation" begins. The Tribulation period, which will last for seven years, does not start at the Rapture of the church, as many believe, but starts the day the Antichrist signs this peace agreement with Israel. That could be a day after the rapture, it could be a week after the rapture, a month or even a year or two. No one knows.
What is the Tribulation? The Tribulation is a seven year period of time that will be characterized by cosmic disturbances, wars, bloodshed, famines, diseases, persecution of Jews and Christians, and many, many other unpleasant events. It will be the worst time of human history in which to live. That is why people will want to follow a leader who they believe has the answers, and at first this Antichrist will seem to fit the bill.
A good chunk of the world hates Israel. The United States, on the other hand, is the best friend that Israel has. When the rapture happens, the U.S. could lose a fourth to a third of its population. Military leaders will be lost, political leaders will be lost, and spiritual leaders will be lost. To say the least, the U.S. will be weakened significantly, which leaves Israel in a somewhat vulnerable position. Many Jewish people know that evangelical Christians are, if not their best friends, then their very good friends. But evangelical Christians are now gone. So when the Antichrist steps in to promise to protect them, it will be quite a significant bit of welcome news, and many Jewish people will welcome him with open arms.
So, to review, in our view the Bible predicts the following will happen sometime in the future: Jesus will come and rapture believers into heaven, undoubtedly leaving the world in complete chaos. A world leader, possibly from the E.U, will arise and form a one-world government, with the help of the False Prophet and 10 (trimmed down to 7) leaders, all reporting to him. Antichrist (remember "anti" means "false," not "opposite"), will sign a peace treaty with the nation of Israel, promising to protect it. The day the Antichrist enforces this peace covenant with Israel, is, according to the Bible, the first day of the seven year Tribulation period.
Certainly one way to endear yourself to the Jewish people if you're a world leader would be to assist in helping to get a temple built in Jerusalem.