I was speaking with a friend recently about the Millennium. She asked why or how there could be unbelievers during the Millennial reign of Christ and the saints. Could you please explain, and cite any Scripture to support your explanation? Thank you so much.
When the Lord comes back to judge the nations at the 2nd Coming, there will be both believers and unbelievers alive on earth who’ve survived the Great Tribulation. The believers are ushered into the Kingdom and the unbelievers are taken off the planet. This is explained in the Sheep and Goat judgment of Matt. 25:31-46.
The believers, still in their natural states, will re-populate the Earth. Their children, being born with a sin nature, will have to choose to accept Jesus or not, just like their parents did. As incredible as it seems, many will reject Him. We know this because at the end of the Millennium, when Satan is set free, he is able to recruit a massive army in one last effort to re-take the planet. This effort will fail and Satan will finally be defeated for good. (Rev. 20:7-10).