LORELAI: Chris, this [sex] is the next to last thing I thought would ever happen tonight. The last thing being a holy saint guy riding down on a flaming chariot from heaven to announce Armageddon.
In the book of Revelations in the Bible, Armageddon is mentioned as the location of a battle at the end of time. Literally, Armageddon refers to an actual place – Tel Megiddo, an ancient city in northern Israel where several Old Testament battles were fought. It’s now in a national park, and has a gift shop attached.
The Bible verse is usually (not always) interpreted symbolically, so that Armageddon is popularly taken to mean any battle between believers and unbelievers at the end of the world, or even more vaguely, any end of times situation involving a clash between good and evil.
Lorelai’s idea of a holy saint riding down in a flaming chariot would thus be the first sign of God’s army arriving from Heaven to announce the battle. The holy prophet Elijah is said to have been taken up to heaven in a chariot of fire, so that might be who Lorelai is thinking of.