This is a great question. This touches the great work of Lord Jesus Christ as it concerns everyone and each individual. Romans is amazing. And Romans 6 is the fulcrum point of the Christian life. It is where we find great application of the Cross. Let me see if I can walk you through it properly.
Paul in Romans 6 is building off of previous chapters and a coherent understanding of the work of the Cross of the Lord Jesus Christ. And understanding this is crucial to understanding chapter 6 and consequently chapters 7 and pretty much all of Paul's theological understanding.
So what did Paul have in mind when he writes this chapter? And how does it apply?
In chapter 5 Paul presents 2 people. Adam and Christ. Adam is presented as the source of our spiritual death and consequently physical death. Physical death we all understand quite readily. Spiritual death is a more difficult thing to understand. But both are crucial aspects of Paul's understanding of Christs work and our relationship to Him and His work.
We are descendants of Adam. You can't get around this. It is just the way it is. Adam is the progenitor of the human race. And this after his fall. It is not easily discerned as you read Romans but Paul includes all in Adam. We are all in Adam. Spiritual death came into our experience because of Adam and consequently physical death.
Most people attribute the Flesh as skin and meat and bones. This is okay but that is not all that it is. It is this but it is also a mindset and a spiritual condition. We receive this at conception and it grows stronger the longer we live in this world without Christ. If you were born you are flesh. It ,the Flesh, can be simply understood as a description of the entirety of the human nature. Body, mind, and spirit. Its all inclusive.
So, as Adam is the progenitor of the flesh, the human race that we all are and how we operate so is Christ of the new creation. Or shall I say of the regeneration. This is not Flesh but Spirit. Amen. I could go into much detail on this but I wont.
So, lets go all the way back to Noah. In Genesis chapter 6 verse 3, we see a dynamic as it concerns the flesh. And we have witness of the Spirit. It says, The LORD said, My spirit shall not always strive with man, for that he also is flesh: yet his days shall be an hundred and twenty years. Then God goes and indicts the entire human race under Adam. All flesh. Noah finds favor and receives instruction on building the ark. Thus receiving salvation and consequently condemnation of the entire human race. All flesh must die.
However, Noah's salvation was not and is not the same as that of Christs. Why? Because he came out the ark the same way he went in. Flesh. Like I said its a spiritual condition. However, there are some correlating factors in the salvation of Noah and the salvation that is in Christ. we don't come out the same way we go in. Its impossible. Death happens as we enter the life. Flesh cannot enter the realm of of Spirit. They are mutual exclusive. We must leave the realm of the flesh (die) in order to enter or be in the realm of the spirit. One is works the other faith.
As the invitation went out from Noah to enter the ark so does the invitation go out for us to enter Christ. For the actual death of Jesus is the door we enter. Yes, the Cross of Christ was not only a sacrifice for sin in the flesh but also an indictment of the entire human race just like Noah and the building of the ark. In this you can know that just as it rained and destroy all flesh, again one day the Lord will appear and destroy all flesh but with fire. Amen.
So, how do we enter the ark. Through death. Through the destruction of the flesh by the spirit. Romans 6,7,8 gives this understanding. Noah built an ark. Jesus is building a body. We are all invited to enter in. The Cross is for everyone but you have to enter on your own. How? Romans 6 is that which points to the door, the finished work of the Cross.
We must be transformed by the renewing of the mind. Our mind must die in order for us to have the mind of Christ. Our hearts must submit to His resurrected life in order to have life. We can't do this on our own. Hence Romans 7. Even if we are believers in Christ we can be such with no actual experience of the power involved.
So what do we do? We must fall upon the sword of the spirit for the destruction of the flesh. The Cross is that sword. So is the ressurection. Its a two edge sword imparting life and death to each of us.
Romans 6:3-4 speak of most of what we have already talked about. The overall inclusivity of the cross of Christ. And shows that baptism correlates to this understanding. What goes in the water must stay in the water. It is a great divide. When you get baptized you are saying that you believe in and agree with Christs indictment of the human race, of all flesh and that you in baptism commit to His life of the resurrection. Its actually His life that puts to death you completely. Its a process and its progressive but its complete. Your commitment to him at the right hand of God and to His real body, the church, which you are a real member in faith with the previous understanding is the key to walking in the power of the gospel.
Real quick. There are two lives that you have as a Christian. Yours and Christs. And these are completely and mutually exlusive. Your life is called Flesh. Christ's is called Spirit. They do not intertwine. No matter how good your life looks or the things you do, it and they are flesh. No matter what. So, deny yourself, this is the death, and take up the cross, this is His life, and follow Jesus always in these two Great aspects of his work.
In Romans 6:9 we see that Christ was raised from the dead and dieth no more. And that death no longer has power over Him. The dead as according to scripture includes all that are under Adam. All participants in the flesh. We can be living in the flesh and yet be dead in the spirit. Flesh and spirit are like to realms and two powers. The power of the flesh is death. The power of the spirit is life. Death derives its power in the flesh from sin, (unrighteousness). Something that God does not deal with. Life derives its power in the spirit from faith, (righteousness of Christ). Another way of saying this is, walk in the flesh, which is sinful, and death has dominion over you. You get paid death. Death is the opposite of life. Death is weakness. It is the incapacity to please God and the incapacity to live true life. Flesh, Sin, and Death are the realms, actions, and consequences on every level for all of mankind without God. These things do not go away even when one is saved.
Christ participated in the flesh yet without sin. So Death had no power over or in Him. He is the righteousness of God. This puts Him in the perfect spot to redeem and sanctify mankind. He was never stung by the sting of death, Sin. Death had no jurisdiction to operate. It is sin that gives Death jurisdiction. For Christ is Righteousness. Death does not have jurisdiction over the righteous. Christ is the only one that is like this. And in fact righteous has jurisdiction over death in a superceding fashion.
When Jesus accepted the Cross and submitted to the will of God by following through with it all they way into the deepest realm of Death he could not be held there because of His righteousness. Death could not keep Him. For He is righteousness. Thus his resurrection. He was already over death for he had the power of life. He is the life.
Adam caused us all to be separated from the life of God and all that entails. World without end. This cannot be changed. Its not so much that we sin, (actions) but more so that we are sin,(nature). With this in mind Christ came into the world to participate in the flesh realm as one of us. Completely human but he was not like us by the fact that he was conceived by the spirit and bypassed sin,(sin nature),(not same as flesh) but still was in the flesh. Since all flesh must die so must christ. Yet He was without sin nature. He was in fact righteous. Death could not hold Him.
So he suffered death in all its forms completely as though He was sin though he was actually righteous. This created a new path to a new realm for all of us that are in the realm of Adam. The new realm of christ. He did this, suffered death, in a righteous way. He came and included himself in our experience. Completely, once and for all. In this He provides a way for us to be included in his experience. By identification and faith in what has been being said.
The statement of Romans 6:23 is not just talking about sin as an action but more so as sin as the core of what we are that colors or shall I say gives quality to what we do, sinful actions. Anything we do in and from ourselves brings death from God. Anything in Christ by faith, which necessitates the death of the old man, because where there is faith, works of the flesh cannot be and where there are works of the flesh, faith cannot be, is life. Christ is the gift. Paul here in 6:23 is talking about cause and effect. Flesh works for death, and faith for life in Christ. Another to say this is faith in Adam results in death, but Faith in Christ results in the Death of Adam and life before God. That life is Like the offering of Abel, it is the life of christ. Unlike the offering of Cane which is the life of the flesh.
Christ is our life.