The verses of Romans 8:1-9 are talking about how in Christ, we are no longer under condemnation and guilt due to sin. Christ came and took our sin and nailed it to His cross. The Old Testament Law, which was a tutor and guide to show us our need of a Savior, was fulfilled, it was crucified and buried with Christ.
When it talks about the flesh, it is talking about those who are not saved and still under the tutor of the Law. They are still under condemnation and guilt because they, in the flesh, cannot please God, whether they try by their good works or don’t try at all. There is nothing they can do to make things right. They are still in the flesh, or another way of saying it, in the spirit of Adam.
Being in the Spirit is to be saved through Christ. You are in the Spirit, if indeed the Spirit of God dwells in you. And we know that if we have accepted Christ’s gift of salvation, the Spirit comes and lives in us. We are the temple of the Holy Spirit. We are now living in the Spirit. We are hidden in Christ, seated with Him at the right hand of the Father. Our spirit man is perfect and holy because of Christ. The old sinful nature has been crucified with Christ and we have been raised as new creatures in Him.
Although we still have a body that is imperfect, and a mind that needs to be renewed…our spirit man has been raised up in Christ as a new creature.
Praise God that we are no longer under condemnation, guilt and shame that the Law brought upon us. We are now the righteousness of God. We can now live in the freedom that Christ provided for us.