the reality of the old man being put to death once and for all.
You quote no proof of this, but since I spent a long time researching out the Old Man and the flesh, I will share my conclusions:
1) the Flesh is an active force in the Christian life (Gal 5: The flesh lusts).
2) By comparing the Flesh (old human nature) with the Old Man, there are no distinguishing characteristics whereby one would be any different from the other. I conclude they are the same.
3) the old man was co-crucified with Christ by our baptism into Christ (not water) Rom 6. Neither death nor crucifixion implies non-existence. Death is separation; the Old Man has been decisively separated from the one who trusts Christ as Savior, but it can spring into action at any time (Rom 7: when the commandment came, sin revived, & I died). The Old Man & New Man are alternative morphai or clothes that a Christian can wear (Ephesians, Colossians, Rom 13).
I think the establishment of the doctrine of the Old Man is beyond my time on this thread. Some Christians deny that the Old Man is yet around -- yet they can still endorse Eternal Security. Some distinguish the Old Man & the Flesh, which I don't think is possible.
If I am correct that beget/begat/begotten passages of 1 John & Peter imply that the new nature cannot sin, an old nature must be necessary to account for sin in the Christian life.
But I think this goes beyond this thread & what is necessary to establish that the Lord actually gives eternal life to the believer.
1 Pet 1
Blessed
be the God and Father of our Lord Jesus Christ, who according to his great mercy begat us again unto a living hope by the resurrection of Jesus Christ from the dead, unto an inheritance incorruptible, and undefiled, and that fadeth not away, reserved in heaven for you, who by the power of God are guarded through faith unto a salvation ready to be revealed in the last time.
THE OVERCOMER
Revelation 3:5
The one who overcomes will be clothed thus in white garments, and
I will never blot his name out of the book of life. I will confess his name before my Father…
1 John 5:4-5 For whatsoever is begotten of God overcometh the world: and this is the victory that has overcome the world,
even our faith. And who is he who overcomes the world, but
he that believeth that Jesus is the Son of God? For everyone who has been born of God overcomes the world. And this is the victory that has overcome the world—our faith.
And I saw the holy city, new Jerusalem, coming down out of heaven from God, made ready as a bride adorned for her husband. And I heard a great voice out of the throne saying, Behold, the tabernacle of God is with men, and he shall dwell with them, and they shall be his peoples, and God himself shall be with them,
and be their God: and he shall wipe away every tear from their eyes; and death shall be no more; neither shall there be mourning, nor crying, nor pain, any more: the first things are passed away. And he that sitteth on the throne said, Behold, I make all things new. And he saith, Write: for these words are faithful and true. And he said unto me, They are come to pass. I am the Alpha and the Omega, the beginning and the end. I will give unto him that is athirst of the fountain of the water of life freely. He that overcometh shall inherit these things; and I will be his God, and he shall be my son. But for the fearful, and unbelieving, and abominable, and murderers, and fornicators, and sorcerers, and idolaters, and all liars, their part shall be in the lake that burneth with fire and brimstone; which is the second death.
In II Thess. 3:3 “But the Lord is faithful, who shall establish you, and guard you from the evil one.”
In II Tim. 1:12 “For I know Him whom I have believed, and I am persuaded that He is able to guard that which I have committed unto Him against that day.”