You have to back up to see who Paul was speaking to and he was speaking to those who knew the law,verse 1, the Jew. A Jew was raised to obey the law and if they were redeemed they loved the law. David said this;
Blessed [is] the man that walketh not in the counsel of the ungodly, nor standeth in the way of sinners, nor sitteth in the seat of the scornful.
But his delight [is] in the law of the LORD; and in his law doth he meditate day and night.
This was the heart of a redeemed OT saint. Paul is dealing with Jews who knew the law, loved the law, and who still had great battles with the flesh because they did not fully understand what Christ had done, and because of it felt constant condemnation. Paul is not saying that he himself was practicing sin as a believer as some suggest. Here is why we know that.
In PHL. Paul is giving his pedigree prior to his conversion to show that he was as good as any man and better then most while under the law and even that that did not save him. Look at what he says;
3:4-6 Though I might also have confidence in the flesh. If any other man thinketh that he hath whereof he might trust in the flesh, I more:
Circumcised the eighth day, of the stock of Israel, [of] the tribe of Benjamin, an Hebrew of the Hebrews; as touching the law, a Pharisee;
Concerning zeal, persecuting the church; touching the righteousness which is in the law, blameless.
Paul is saying he obeyed the law while under the law. He was blameless while under the law, so now that he is under grace he is not saying that he was battling sin and losing the battle. We also know Paul was not sinning because of Romans 6:15 What then? shall we sin, because we are not under the law, but under grace? God forbid.
Paul was dealing with those who knew the law and he is trying to get them to see that they are now to serve in spirit not the letter. It is not the flesh that gives victory but the spirit. You have to go ahead and read chapter 8 also.
These that Paul is speaking to are Jews who knew the law, and had heard about Jesus. However they had not made a break with the law and they needed to do that to come all the way to Christ. They were like someone who is in prison for all their life and then one day the jailer opens the door and walks away and instead of leaving, the prisoners stay in the prison. Paul is trying to show them their freedom is not inside the prison (the law) but in Christ (spirit).
So to answer the question Paul is speaking to those who were Jews redeemed under the law, but had heard about Christ and had not made a clear break with the law and needed to come under the authority of the New Covenant.
So Paul is putting himself in the place of these Jews knowing what they are feeling. Their battle of seeking to keep the law through the flesh and feeling condemned when they break the law because now the sacrifices have stopped and they feel condemned.
He is saying that freedom comes with Christ and to see that you have to go to chapter 8.
[There is] therefore now no condemnation to them which are in Christ Jesus, who walk not after the flesh, but after the Spirit.
He is telling them to stop trying to satisfy the law through the flesh and that would include sacrifices and just walk after the spirit and find the peace that comes with being in Christ so as to lose the condemnation they were feeling.
)
