If a person be in Christ, not in religion, in the church or in a moral reformation, but in Christ, by faith in Christ, by a new birth wrought in the soul by the Spirit of God, in Christ through electing love, redeeming grace and a living union, he is a new creature (Gallatians 6:15).
This new creation describes a creation work, not of man but of God (Ephesians 2:8-10). It is a new creature, a new principle of grace and holiness, which was not there before and is distinct from the old nature, the old man, with which we are born in the flesh (John 1-12 plus 13). Old things are passed away, the old way of life, which loves and serves the flesh, the old legal righteousness and religion, old companions and acquaintances, old desires for riches, honor and human philosophic and old foolish thoughts of God, self and future glory.
The new man thinks and acts from new principles, new rules with new goals and objectives and in a new fellowship. He has a new commandment of love, a new name, a new song in his mouth, even praise to God, a new and living way opened by the blood of Christ and an inheritance in the new heaven and the new earth.
In the new creation, absolutely nothing of the flesh is needed, used or continued. Our Lord said, "Behold, I make all things new." That God is able in His mercy, grace and wisdom to make a way for our sins to be laid on a substitute and the guilty sinner to go free is the greatest glory of His nature that He has seen fit to reveal.
The sinner must be changed and changed by God Himself before Divine truth will either be understood or received. Deep views of sin will ever result in deep views of the sacrifice for sin. Remember John the Baptist in (John 3:30) as he declares Christ must increase, but I must decrease. Be satisfied, then, not to rest on the surface of this wondrous truth.
Man cannot be saved by perfect obedience, for he cannot render it; he cannot be saved by imperfect obedience, for God will not accept it.