It seems our situation is different from Adam and the angelic race falling from grace. I think they had the potential to be sinless forever.
In this life, even as we're reconciled with God-or
being reconciled with Him- we will always struggle against the tendency to sin. Had Adam remained subjugated to God, this tendency, this loss of self-control, this "concupiscence" as its called, would've never gained a foothold. With the original sin and its resulting rift between humankind and God, the door was opened for all sins that followed. Once God is no longer the ultimate moral authority, morality becomes
relative for all practical purposes, based on our own determination. So the doorway back to authentic morality or righteousness or justice for man can only be
through God-and this is why Jesus came.
Adam had the potential to remain sinless. According to classic theology he possessed "preternatural gifts", which included immortality, the life of God in him (sanctifying grace), as well as complete self-mastery: the subjugation of all human appetites and passions to reason or the spirit. With his choice, believing a lie, presumably believing what he
preferred to believe, he forfeited all that. And his world changed immediately. He now existed in a world where the threat of death/non-existence loomed, where physical hardship and suffering (or physical evil) existed, and where sin (moral evil) abounded. He would from then on literally, directly, and viscerally
know, by experience, both good and evil. And this is the world we inherit now. It's a good, awesome world. It's an evil, ugly world, made way uglier by certain choices and actions of many of our fellow humans. And none of us are immune from this to one degree or another. Pride and selfishness and jealousy and anger often direct our paths. Man is torn not only from God but also from himself, from his fellow man, and from the rest of creation. He's lost, not knowing where he came from, if anywhere, what he's here for, if anything, and where he's going, if anywhere. And perhaps too dull or distracted by foolishness to care.
But God deemed it wise that humankind should spend time in this very world, with it's good and evil, so that we may hopefully gain the wisdom, with His help, to make the right choice, to reject evil and choose the good alone, to choose
Him ultimately, above all else.
This life is sort of a reprieve, so to speak, in God's justice, but only so that it can serve as a sort of school -of formation- where God works to not merely save the lost, but to save them as He's
perfecting them, bringing them back into a state of justice and then further yet even, ultimately beyond the state Adam knew in Eden, where, while gifted like a spoiled rich kid perhaps, he was unappreciative of all he'd been given, and so, before the Fall, yet neutral in his opinion and choice vis a vis God and obedience to Him. Again, we're here to gain the wisdom to come to make the
right choice, and progressively make it more firmly, to hold it more innately, with the help of grace as we progress along the path He's set out for us.
Man was
made for communion with God. That's obviously not the state we're born into now, a state that would exclude sin by it's nature.