Augustine of Hippo (A.D. 354 – 430) is a luminary of Church history worthy of your acquaintance. (To this writer's knowledge he had nothing to do with the world's most dangerous land animal, the hippopotamus.)
Augustine wrote in Latin, and today we will translate and expound on the following helpful paradigm he bequeathed to posterity:
Posse Peccare
Non posse non peccare
Posse non peccare
Non posse peccare
Posse Peccare means "able to sin." This was the stage, or condition, of the will of Adam and Eve when they were created. We know that they were able to sin, because they did so! And Romans 5:8 tells us the tragic result: sin spread to all Adam's descendants, except to that One Who was virgin born and Who saves us from sin, Jesus our Lord.
God had told Adam and Eve that on the day they sinned, they would die. And so they did. Although their bodily life continued for centuries (cf. Genesis 5:5), spiritual death occurred at the moment that they sinned. Their terror at God's approach, their blameshifting when He confronted them and the eventual outward acts of human sin as per the world's first fratricide by Cain against Abel make this sadly clear. Mankind was now fallen. In Adam, we all became…
Non posse non peccare, which means not able to NOT sin. Ephesians 2:1 puts it this way, "And you were dead in the trespasses and sins." And Romans 3 proclaims that every naturally born human being is a creature incapable of righteousness. Thankfully, God did not leave His elect in that woeful condition! When the Holy Spirit regenerates someone, thus giving them the capacity to repent and believe the Gospel, that one becomes…
Posse non peccare, which means able to not sin. Alert! We need to be careful to avoid the error of perfectionism here; the teaching that a Christian can become sinless in this earthly life. We cannot. But don't worry, perfection will come in God's time, read on!
For now, what is the condition of those united to Christ by faith, sharers in the covenant of redemption, those who have been made partakers of His Spirit? (And if one does not have the Spirit of Christ, that one does not belong to Him, cf. Romans 8:9). We are no longer under the dominion of sin, even though sin still clings us, to our grief. Our life long path of discipleship includes warfare against that indwelling sin.
"…let us also lay aside every weight, and sin which clings so closely, and let us run with endurance the race that is set before us." (Hebrews 12:1 B)
When the battle is over, the Christian goes to be with the Lord and is finally Non posse peccare, which means not able to sin. Hallelujah! Describing what being in Christ means even now for us who remain below, the writer to the Hebrews includes a key statement about those who have gone above:
"…you" [who are still on Earth] "have come to Mount Zion and to the city of the living God, the heavenly Jerusalem, and to innumerable angels in festal gathering,and to the assembly of the firstborn who are enrolled in heaven, and to God, the judge of all, and to the SPIRITS OF THE RIGHTEOUS MADE PERFECT…" (Hebrews 12:22,23)
But even that is not all. Just as in Eden spiritual death preceded bodily death, so now the perfection of the spirit upon bodily death is succeeded by the resurrection of the body. And what a resurrection it will be!
"Who" [the Lord] "will transform our lowly body to be like His glorious body, by the power that enables him even to subject all things to Himself." (Philippians 3:21)
"So is it with the resurrection of the dead. What is sown is perishable; what is raised is imperishable. It is sown in dishonor; it is raised in glory. It is sown in weakness; it is raised in power. It is sown a natural body; it is raised a spiritual body. If there is a natural body, there is also a spiritual body." (1 Corinthians 15:42 – 44)
So the final state or condition of the will of a redeemed one, in fact of the entire being of every saint, is never being able to sin again. Has a troubling question ever arisen in the back of your mind, namely "what if sin happens again in heaven?"
NOT GONNA HAPPEN! Having been fully conformed to Christ, united to Christ, being a member of His mystical body, the Church…His eternal bride, could that be? No way! Non posse peccare, not able to sin for all eternity.
Oh the depth of the wisdom and perfection of the Pactum Salutis, that is the Holy Trinity's covenant of redemption!