When believers are in heaven or in the 1000 year reign of Christ will we still have free will?
During the Millennium believers on Earth will retain their free will. But 1 Cor. 15:24 says,
Then the end will come, when he hands over the kingdom to God the Father after he has destroyed all dominion, authority and power.
At the end of the Millennium, when the Lord turns the kingdom over to His Father, He will destroy all dominion, authority and power. The primary meaning of the Greek word for authority is “the power of choice, liberty of doing as one pleases.” To me this means that in eternity mankind will no longer have free will, and there will finally be only one will in all of creation, the will of God.