The 1290 Days Prophecy is from Daniel 12:11-12, which states:
- "And from the time that the daily sacrifice is taken away, and the abomination of desolation is set up, there shall be one thousand two hundred and ninety days. Blessed is he who waits, and comes to the one thousand three hundred and thirty-five days."
While there has been some debate in Bible eschatology circles over what this prophecy actually means, the Left Behind books interpret it in the following fashion: 1290 days after the Antichrist had defiled the Temple (30 days following the end of the Tribulation), God destroyed the Temple with a single powerful lightning bolt. 1335 days following that defilement (75 days following the end of the Tribulation), the new Temple built by Jesus is set up and dedicated, thus beginning the Millennial Kingdom period.