Sinlessness in eternity

I used to often wonder about the Christian's future life in heaven and about how that life would be played out. One of the things that troubled me was the doubt about our ability to remain, for eternity, in a state of sinlessness. I figured, Adam and Eve lived as sinless beings and walked with God and yet they sinned. What is to insure and assure us against sinning in our afterlife; eternity is a long time.

One of the errors I was making in these thoughts was that I had wrongly assumed that the atoning work of Christ was an attempt to 'get us back to the garden.' I thought our goal in the Christian life was to become, once again, like Adam and Eve. Now, there is some truth to these ideas, but they fall short of the purpose of God's work in Christ on our behalf.

Walter Marshall discusses this in The Gospel Mystery of Sanctification, saying:

... Christ aimed at a higher end in His incarnation, death and resurrection, than the restoring the decay and ruins of our natural state. He aimed to advance us to a new state, more excellent than the state of nature ever was, by union and fellowship with Himself, that we might live to God, not by the power of a natural free will, but by the power of His Spirit living and acting in us.

We can rest assured that eternal bliss will not be interrupted by iniquity because we are not being made like Adam. Rather, we are being made like Christ. And our union with Christ by the Holy Spirit seals this eternally. Praise God.