Will believers rule and reign with Christ on earth in the future kingdom?
Yes. The kingdom of His dear Son, into which believers are translated at salvation, will one day be established on earth. This same kingdom, now in heaven, will include believers, who will be there and will rule and reign with Christ over that future kingdom.
Les explains that John the Baptist announced the kingdom of heaven was at hand because the King was in Israel's midst, and where the King is, the kingdom was sure to come. But Israel rejected the King and the kingdom and crucified Him; He was called back up into glory and seated at the Father's right hand. Yet nothing regarding His kingship and kingdom has really changed. He remains King of kings and Lord of lords, though Les maintains He is not the King of the church but the head of the body. The kingdom remains centered in Christ. At salvation, God translated believers out of spiritual darkness into the kingdom of His dear Son, which is now in heaven. That same kingdom will one day yet come and be established on earth, and believers will be there with it, ruling and reigning with Christ over the kingdom they now belong to through salvation. Les also notes this deliverance is past tense: He has delivered us from the power of darkness, which includes Satan, principalities and powers upon the human race, and the little Adam.