The Bible describes heaven or the eternal state in great detail in Revelation chapters 21–22. Nowhere in those chapters is the possibility of sin mentioned. In fact, we have the promise that, in the eternal state, we will never experience death, sorrow, crying, or pain (Revelation 21:4)—the absence of those things is proof positive that sin is also absent, since those things are the product of sin (see Romans 6:23).
The sinful will not be in heaven but in the lake of fire (Revelation 21:8). Nothing impure will ever enter heaven (Revelation 21:27). Outside of heaven are those who sin (Revelation 22:15). An Old Testament prophecy also assures us that the Kingdom of God will exclude sinfulness:
“A highway will be there;
it will be called the Way of Holiness;
it will be for those who walk on that Way.
The unclean will not journey on it;
wicked fools will not go about on it. . . .
But only the redeemed will walk there” (Isaiah 35:8–9).
So, the answer is, no, it will not be possible for us to sin in heaven.
God wills our sanctification (1 Thessalonians 4:3); that is, He wills to make us holy and free of sin. Our sanctification has three phases: positional sanctification, which saves us from the penalty of sin at the moment of faith in Christ; progressive sanctification, which saves us from the power of sin as we grow in Christ; and complete sanctification, which saves us from the presence of sin as we enter the presence of Christ. “When Christ appears, we shall be like him, for we shall see him as he is” (1 John 3:2). In other words, the process by which God sanctifies us involves justification, maturation, and glorification.
The glorification that God promises His children (Romans 8:30) necessarily includes sinlessness, because sinful beings cannot be glorious. Heaven, the place of God’s glory, is sinless. Paul prays in 1 Thessalonians 5:23, “May the God of peace himself sanctify you completely” (ESV), and he links the glorious appearing of Christ to our personal glorification: “When Christ, who is your life, appears, then you also will appear with him in glory” (Colossians 3:4). This glorified state will be our ultimate separation from sin, a total sanctification in every regard. It will not be possible for us to sin in heaven.
James 1:14 provides another assurance that we will not sin in heaven: “Each person is tempted when they are dragged away by their own evil desire and enticed.” In this sinful world, we face temptation daily, and James identifies two forces that prompt us to sin: our own evil desire (our sin nature) and enticement (the devil’s schemes). Neither of those forces will be in heaven. Our sin nature will have been eradicated in our glorification, and the tempter will have been consigned to the lake of fire where he can do us no harm (Revelation 20:10).
The Bible’s teaching is that heaven or the eternal state is completely holy. There will be no possibility of sin, we will be clothed with righteousness (Revelation 19:8), and we will be eternally confirmed in our state of bliss. The work that God promised to complete in us will have been finished (Philippians 1:6). Our deliverance will be complete, as the elect are redeemed—body, soul, and mind—to the glory of the Lamb (Revelation 5:6–10).