Satan Bound

https://www.lds.org/manual/gospel-principles/chapter-45-the-millennium?lang=eng 

During the Millennium, Satan will be bound. This means he will not have power to tempt those who are living at that time (see D&C 101:28). The “children shall grow up without sin unto salvation” (D&C 45:58). “Because of the righteousness of [the Lord’s] people, Satan has no power; wherefore, he cannot be loosed for the space of many years; for he hath no power over the hearts of the people, for they dwell in righteousness, and the Holy One of Israel reigneth” (1 Nephi 22:26).