This is the factual state of every believer regarding our "body" and "sin." This does not keep us from fellowship.
Romans 8:10
And if Christ be in you,
the body is dead because of sin; but the Spirit is life because of righteousness.
We should readily be able to
perceive the above. We are honest and truthful
in that sight. That is honest fellowship. NOT deceitful lying hypocrisy fellowship, which is no fellowship whatsoever.
Literal physical death is not the measure of the body being dead because of sin. Most will disagree with Paul about the conditions of the natural body of Adam that is depicted in detail by Paul in 1 Cor. 15:43-49. Paul tells us there that Adam, Gods son, was planted in a natural body that was
dishonorable, corrupt and weak. It is DEAD because of sin. These are "always" the states of the natural body. I would note Jesus as the sole exception to these matters because there was no sin in Him.
That does not change the facts of having a body that is dead because of sin. The two are unrelated.
ALL bodies are dead because of sin, believer or unbeliever. It has nothing to do with fellowship. I might even say if we claim we don't have a body that is dead because of sin, we are not truthful before God in Christ, to ourselves or to others, and can't be.
We are instead lying hypocrites, claiming fellowship.
Paul hammers this point home in many ways:
Romans 7:9
For I was alive without the law once: but
when the commandment came, sin revived, and
I died.
We might even note that it was from concupiscence thoughts against the law in Paul's mind that MADE him understand this principle of sin indwelling the flesh being against the law, proven by evil defiling thoughts. Romans 7:7-13. Yes, THOUGHTS were sufficient to prove the case.
Colossians 3:3
For
ye are dead, and
your life is hid with Christ in God.
It is sin in the flesh that will refuse this matter of fact every single time, and causes "believers" to see it otherwise. Yes,
the body IS dead because of sin. There is no way around it.