From which groups will the population increase in the thousand-year Kingdom?

Les explains that after the Tribulation, survivors who heard the message and became believers as Gentiles predominantly will be the seed stock of Gentile nations going into the Kingdom. He also notes that a remnant of Israel went into the mountains southeast of Jerusalem at the midpoint of the Tribulation, was protected by God, and at His second coming they finally become believers as a nation. They will be the beginning of the nation of Israel. So coming into the Kingdom with Christ ruling and reigning as King, the population increases from Gentile believers who survived the Tribulation and from the saved remnant of Israel. Les says this thousand-year period will be a tremendous population explosion because there is no sin, no death, Satan is locked up, and there is prosperity, food production, ideal climate, and a Garden of Eden condition, resulting in increase from all the Gentile nations as well as from the nation of Israel.