During the Great Tribulation the Holy Spirit will act in the same manner he did during the Old Testament.. What will be the role of the Holy Spirit during the Millennial period? And for that matter can or will people get saved during this period? Or not, because Satan is bound therefore there is no evil?
The Bible does not inform us of the Holy Spirit’s role during the Millennium. Nor does it address the issue of salvation during that period. But don’t get the idea that with Satan bound there will be no evil. The Earth will be largely populated by people in their natural states, which includes a sin nature. As Millennial believers bear children those children will have to make a decision for the Lord just as you and I have, and many of them will reject Him.
On Earth, the Millennium will be a repeat of the age of man in many ways, with only believers at the beginning but starting with the second generation, becoming a progressively smaller percentage of of the population as time goes by. At the end, there will be a sufficient number of unbelievers to permit Satan to recruit a large army with which to attack the Lord in one final attempt to regain control of planet Earth. It will of course be unsuccessful (Rev. 20:7-10).
The main lesson of the Millennium is that there is no condition under which natural man can live in peace with the Lord. Given the opportunity, he will always rebel.