Why will children born during the millennial kingdom not be able to rebel?
They will not be able to rebel because no satanic force is operating and Christ rules as King with absolute benevolent power. That removes the opportunity for out-and-out rebellion, even though these children are still born with the same old Adamic nature as their parents.
Les explains that the children born to believers in the kingdom will have no opportunity for out-and-out rebellion because there is no satanic force operating and Christ will rule with absolute benevolent power as King. Even so, they are born with the same old Adamic nature as their parents. At the end, Revelation says Satan is going to have to be released for a little season so this new generation—who never had to choose for or against God—can be brought to a place of choosing. They must exercise free will, as everyone does. Choice requires more than one option, so Satan returns to present his options, just as he tempted Eve. Though the Kingdom is glorious, he will tempt them with the same idea: you can be like God.