How Eternal is Eternal Life?

I was asked an interesting question recently, which I will paraphrase this way:

Will there be Free Will and/or danger of falling again into Sin in Heaven?

There are two parts to this question. The first deals with our will, and the second deals with our security.

Let us begin with the will. Much is made of Free Will. Free will, in its truest meaning, is possessed only by God Himself. He has complete understanding of every situation, cannot be influenced by things 'outside of His control' (clearly), cannot be intimidated, bought, or act from a corrupt motive. He is free, every time, to make the best decision.

Nobody questions His free will, yet there are clearly things he "cannot" do. He cannot tempt or be tempted to sin(James 1:13), He cannot lie (Titus 1:2) He cannot deny Himself (2 Tim 2:13). Are we perhaps misunderstanding "free will"?

Luther said this about the free-will (so-called) in his famous 'Bondage of the Will"

You describe the power of "free-will" as small, and wholly ineffective apart from the grace of God. Agreed? Now then, I ask you: If God's grace is wanting, if it is taken away from that small power, what can it do? It is ineffective, you say, and can do nothing good. So it will not do what God or His grace wills. Why? Because we have now taken God's grace away from it, and what the grace of God does not do is not good. Hence it follows that "free-will" without God's grace is not free at all, but is the permanent prisoner and bondslave of evil, since it cannot turn itself to good.

Our will is not so free as we suppose when we begin, because we cannot, as fallen man, decide to be redeemed. We are dead in ourselves and must be made alive in Christ.

Romans 6:17-18 puts it this way:

¹⁷But thanks be to God that, though you used to be slaves to sin, you wholeheartedly obeyed the form of teaching to which you were entrusted. ¹⁸You have been set free from sin and have become slaves to righteousness.

It works this way: You were once completely independent of an appetite for righteousness (Rom 6:20) you sinned, willingly and gladly. Put differently - you sinned of your own free will. What happens when you are Redeemed? You experience a New Birth. There is an internal overthrow of the Old and it begins to be replaced by the New. (1 Cor 5:17) We have new affections. We desire different things. We desire His Goodness, His kingdom. We Cherish His Lordship. Do we stumble? Yes. We are not yet conformed to His Image. But it grieves us. We cry out to Him for forgiveness (1 John 1:6-10) and strength to walk in Union with Him. This process of being transformed by the renewing of our minds is Sanctification.

We have the Surety (or down-payment) of our Redemption, none less than the Holy Spirit Himself.

We will be transformed, not merely in our bodies, but in our understanding, also. This mortality will put on immortality. We will no longer see in the glass darkly, but then face-to-face.

So, once we have been redeemed, we look forward to that great day when the promise becomes the reality.

The question, again, is can we lose our salvation once in Heaven?

I will ask you a question: Which has greater effect? Sin or Grace?
Romans 5:20-21 answers that for us. Sin abounds but Grace abounds much more.

Sin reigns over the sinner. To what end? Death and Hell. For how long? Eternally.
Can the condemned sinner ever "lose" his damnation? No. "It is where the worm does not die, and the fire is not quenched. " or again.. "the smoke of their torment ascends forever and ever and they have no rest day or night"

Romans 5:21 which tells us that sin reigns over the sinner to death, also tells us that grace reigns through righteousness unto eternal life through Jesus Christ.

Quickly breaking this down, arguing from the lessor to the greater: If we are confident that the eternal punishment is unyielding, unrelenting and undiminished for all eternity, what are we to suppose is meant by Grace (God's gift, not our effort) ruling?
How long is this rule? Eternal.
What is the eternal gift? Life.
By who or what is this gift provided? Through Jesus Christ Himself.

Still need assurance?
How about this?

One is Daniel's prophesy (remember that Son of Man is what Jesus called Himself)

¹³ “ I was watching in the night visions,
And behold, One like the Son of Man,
Coming with the clouds of heaven!
He came to the Ancient of Days,
And they brought Him near before Him.
¹⁴ Then to Him was given dominion and glory and a kingdom,
That all peoples, nations, and languages should serve Him.
His dominion is an everlasting dominion,
Which shall not pass away,
And His kingdom the one
Which shall not be destroyed.

His possession, which He bought with His blood cannot be taken from Him, and it will not be diminished or destroyed. It shall not pass away. We are that possession purchased with His blood (Rev 5:9; 1Pet 1: 18-19).

He said of us: (John 10:27-29)

²⁷My sheep hear my voice, and I know them, and they follow me: ²⁸And I give unto them eternal life; and they shall never perish, neither shall any man pluck them out of my hand. ²⁹My Father, which gave them me, is greater than all; and no man is able to pluck them out of my Father's hand.

Are you concerned that you may yet be tempted in a place that has no need of Sun or Moon but that God Himself will be its illumination? In a place where there will be no night!

Remember that it is given unto man to die ONCE, and after that judgment (Heb 9:27)

Consider: Rev 21:27 -- nothing that defiles, nor abominations, nor anything that causes a lie shall enter, but only those in the Lamb's book of life.

And again: Rev 22:3

And there shall be no more curse, but the throne of God and of the Lamb shall be in it, and His servants shall serve Him.

[If you do not see a curse, sin must be absent, because Sin is linked to the curse throughout the Bible.]

And if that were not enough: Rev 22:4

They shall see His face, and His name shall be on their foreheads.

Be encouraged. Stand strong. Put on the armor of light.
Your salvation is nearer now than when you first believed.