I agree, roman6and6. But I would also add to this that there is a difference between having an occasional struggle with sin and living a lifestyle of sin. Would you agree? Also, how would you define being 'in the flesh' and 'in the Spirit'?
Blessings
I would define "in the flesh" as in Galatians 5 and in Romans 8:1-9, as the sin nature.
Gal 5:16-25
16 This I say then, Walk in the Spirit, and ye shall not fulful the lust of the flesh.
17 For the flesh lusteth against the Spirit, and the Spirit against the flesh: and these are contrary the one to the other: so that ye cannot do the things that ye would.
18 But if ye be led of the Spirit, ye are not under the law.
19 Now the works of the flesh are manifest, which are these; Adultery, fornication, uncleanness, lasciviousness,
20 Idolatry, witchcraft, hatred, variance, emulations, wrath, strife, seditions, heresies,
21 Envyings, murders, drunkenness, revellings, and such like: of the which I tell you before, as I have also told you in time past, that they which do such things shall not inherit the kingdom of God.
22 But the fruit of the Spirit is love, joy, peace, longsuffering, gentleness, goodness, faith,
23 Meekness, temperance: against such there is no law.
24 And they that are Christ's have crucified the flesh with the affections and lusts.
25 If we live in the Spirit, let us also walk in the Spirit.
Rom 8:1-9
8:1 There is therefore now no condemnation to them which are in Christ Jesus, who walk not after the flesh, but after the Spirit.
2 For the law of the Spirit of life in Christ Jesus hath made me free from the law of sin and death.
3 For what the law could not do, in that it was weak through the flesh, God sending his own Son in the likeness of sinful flesh, and for sin, condemned sin in the flesh:
4 That the righteousness of the law might be fulfilled in us, who walk not after the flesh, but after the Spirit.
5 For they that are after the flesh do mind the things of the flesh; but they that are after the Spirit the things of the Spirit.
6 For to be carnally minded is death; but to be spiritually minded is life and peace.
7 Because the carnal mind is enmity against God: for it is not subject to the law of God, neither indeed can be.
8 So then they that are in the flesh cannot please God.
9 But ye are not in the flesh, but in the Spirit, if so be that the Spirit of God dwell in you. Now if any man have not the Spirit of Christ, he is none of his.
In other Scriptures the flesh may mean the physical body, or simply human reasonings and effort.
Paul contrasts the flesh with the spirit in Galatians and Romans in the above Scriptures and actually connects the flesh with the "works of the flesh" in Galatians. In Romans he states that those who are in the flesh cannot please God.
In Romans he says that the child of God is not in the flesh but in the Spirit because the Spirit of God dwells in them. In Galatians he say that the child of God has crucified the flesh with its affections and lusts.
The flesh in these Scriptures are talking about the sin nature, and this is what was crucified with Christ through the death of His flesh on the cross.