The flesh opposes the work of the Spirit and leads the believer toward sinful behavior he would not otherwise be compelled to do.
The believer does not have two competing natures, the old and the new; but one new nature that is still incarcerated in unredeemed flesh. But the term “flesh” is not equivalent to the physical body, which can be an instrument of holiness.
Our mortal body is the only remaining repository where sin finds the believer vulnerable. The brain and its thinking processes are part of the body and thus tempt our souls with its sinful lusts.
Christians must wait until their glorification before they are finally rid of their unredeemed humanness (Romans 8:23), yet by walking in the Spirit they can please God in this world.
Commentary from the MacArthur study Bible, notes for Galatians 5:17 and 5:24; Romans 6:6 and 6:12.
Notes. For anyone who is interested in the extreme or hyper grace teaching, while we who believe in the Lord Jesus Christ are forgiven our sins, let us not forget the warning in Galatians 5:19-21 and others:
Now the works of the flesh are evident,
which are: adultery, fornication, uncleanness, lewdness,
idolatry, sorcery, hatred, contentions, jealousies,
outbursts of wrath, selfish ambitions, dissensions,
heresies, envy, murders, drunkenness, revelries, and the like;
of which I tell you beforehand, just as I also
told you in time past,
that those who practice such things
will not inherit the kingdom of God.
Our obedience reflects our love for our Savior (John 14:15; 1 John 5:3). If we are following our sinful desires, we then have to question if we love the Lord, or if in reality we are actually walking away from Him.
Do not love the world or the things in the world.
If anyone loves the world,
the love of the Father is not in him.
For all that is in the world-
the lust of the flesh, the lust of the eyes,
and the pride of life-
is not of the Father but is of the world.
1 John 2:15-16
Beloved, do not imitate what is evil,
but what is good.
He who does good is of God,
but he who does evil has not seen God.
3 John 11
Here is more about the hyper-grace teaching and how it conflicts directly with other Scripture: https://www.gotquestions.org/hyper-grace.html.
The freedom Christians have is not a base from which they can sin freely and without consequence. Christian freedom is not for selfish fulfillment, but for serving others.
This does not mean God has abrogated His moral law (Romans 3:21). We are indeed under grace (Romans 6:14), but the Lord also guides and teaches us in the behavior He expects, by giving us His words and Spirit as that guide.
Commentary from the MacArthur study Bible, notes for Galatians 5:13, Romans 6:14.
A believer’s unregenerate self – “our old man”. The Greek word for “old” does not refer to something old in years but to something that is worn out and useless. Paul uses the term “body” and “flesh” to refer to sinful propensities that are intertwined with physical weaknesses and pleasures. But the term “flesh” is not equivalent to the physical body, which can be an instrument of holiness.
Commentary from the MacArthur study Bible, notes for Romans 6:6.