“Flesh” vs “Flesh”: In Scripture, “flesh” has two primary definitions and in the Greek it is pronounced “sarx.” Nearly always in the OT it refers to “the soft substance of the living body, which covers the bones and is permeated with blood of both man and beasts.” Nearly always in the NT it refers to “mere human nature, the earthly nature of man apart from divine influence, and therefore prone to sin and opposed to God” (https://www.blueletterbible.org/lang/Lexicon/Lexicon.cfm?strongs=G4561&t=KJV). Concerning the human nature—“flesh,” it is the sinful Adamic nature, and knowing this, esp. when studying the NT will help explain many passages in Scripture. For example, when John 1:14 writes that “the Word became flesh” it is referring to the human physical body and not the human sinful nature, for the Lord Jesus was ever without sin within Him, but was momentarily “on Him” (Isa 53:6). When Galatians 5:17 writes “the flesh desires against the Spirit, and the Spirit against the flesh” it is referring the sinful nature, for the physical body has no mind or will thus no nature, it is merely an object used by such and is subject to pleasures and infirmities which derive from the nature. - NC Finished Facts As the believer strives to walk worthy of the Father and well-pleasing to Him in all things, he is often sorely troubled at the power of indwelling sin, and asks what the cause may be that he so often fails in conquering it. The answer to this question he ordinarily finds in his want of faith or faithfulness, in his natural feebleness or the mighty power of Satan. Alas, if he rests content with this solution. It is well for him if he press on to find the deeper reason why all these things, from which Christ secured deliverance for him, still can overcome him. One of the deepest secrets of the Christian life is the knowledge that the one great power that hinders the Spirit from ruling, that the last enemy that must yield to Him, is the flesh. He who learns what the flesh is, how it works and how it must be dealt with, will find freedom. It is to discover the truth of God concerning the flesh, both in its service of God and of sin, that Galatians was written. Paul wants to teach them how the Spirit, and the Spirit alone, is the power of the Christian life; and how this cannot be except as the flesh, with all that it means, is entirely held inactive. And in answer to the question how this can be, he gave the wonderful answer which is one of the central thoughts of God’s revelation. The crucifixion and death of the Lord Jesus is the revelation not only of an atonement for sins, but of a power which frees from the actual dominion of sin itself, as it is rooted in the flesh. When Paul in the midst of his teaching about the walk in the Spirit tells us, “They that are Christ’s have crucified the flesh and its passions and lusts,” he tells us what the only way is in which deliverance from the old man is found. To understand this word, “crucified the flesh,” and abide in it, is the secret of “walking not after the flesh but after the Spirit.” “The flesh”—in Scripture this expression means the whole of our Adamic nature in its present condition under the power of sin. It includes our whole being—spirit, soul and body. After the fall, God said, “man is flesh” (Gen 6:3). All his powers, intellect, emotions, will—all are under the power of the flesh. But the Word says, “They that are of Christ Jesus have crucified the flesh.” Men often speak of crucifying the flesh as a thing that has to be done. Scripture always speaks of it as a thing that has been done, an accomplished fact*. “Knowing this, that our old man was crucified with Him.” “I have been crucified with Christ.” Everyone who accepts Christ receives Him as the Crucified One, receives not only the merit, but the power of His crucifixion, is united and identified with Him, and is called on intelligently and voluntarily to realize and count upon that identification (Rom 6:11). “They that are of Christ Jesus” have, in virtue of their accepting the crucified One as their life, given up their flesh to the Cross which is of the very essence of the person and character of Christ as He now lives in heaven; they “have crucified the flesh with its passions and lusts.” If I know the Cross in its Substitution, but not, as Paul gloried in it, in its Fellowship (Gal 6:14), I never can experience its power to sanctify. As the blessed truth of its Fellowship dawns upon me, I see how by faith I enter into and live in spiritual fellowship with the Lord Jesus who, as my Head and my Life, made and proved the Cross the only ladder to the Throne. Hence I accept the Cross, with its death to what is flesh, secured to me in the Lord Jesus, as the only way to become free from the power of the old man, and to walk in the new life by the Spirit of Christ. - Andrew Murray Poster’s Opinion: *”Scripture always speaks of it as a thing that has been done, an accomplished fact”: It is the Spirit using the power of the “Cross,” which was effected by Christ that establishes crucifixion of the believer upon rebirth and through the believer’s entire Christian walk. This is the Cross which judges and condemns sin (Rom 8:3) and also restrains (as one still alive on the cross but restrained from dominating—Rom 6:6) the “old man” (flesh; sinful nature) from ruling (Rom 6:12, 14) the believer, but does not restrain from tempting the believer (Rom 7:17, 20). The “cross” which we take up daily (Luke 9:23) does not involve power over sin but reveals established power over sin, which the Lord has effected and which the Spirit applies. The believer’s cross manifests God’s power over the dominion of sin as the believer “endures hardness” (2Tim 2:3) by way of God’s enablement (1Cor 10:13). Through our Christian life God progressively increases our maturity level in this all important part of the Christian walk, which makes us “partakers of Christ's sufferings” (1Pet 4:13). We see our instruction in this the most by being more patient in each hardness (“trial”) through knowing that whatever the difficulty, it is already, without fail, purposed by God for our “good” (Rom 8:28). This includes any and all occurrences, regardless whether or not we unintentionally produced it by error.