There is therefore now no condemnation to them which are in Christ Jesus, who walk not after the flesh, but after the Spirit – Romans 8:1
Here we find two descriptions of the same person — the person that is in Christ Jesus. Those that are in Christ Jesus are described first by their position and then by their practice. They have no condemnation against them, Paul says, and they walk after the Spirit instead of the flesh.
No condemnation! Because God is completely holy, even our greatest deeds and thoughts are sin-soaked, filthy rags in his perfect sight. We stand guilty before a virtuous and fair judge; justice will be served (he will not compromise his own righteousness in order to have mercy on us) and so we must be condemned.
But those who are in Christ have their punishment transferred to Jesus, so that they are without condemnation. Those who believe on Jesus Christ have the assurance that he has taken their place—acted as their substitute—and so, in spite of their great shortcomings, they are without condemnation. Christ's perfect sacrifice on their behalf has wiped their criminal record clean.
How do these pardoned sinners then live? They follow the promptings and leadership of the Spirit of God. As Paul explains a few verses later, "as many as are led by the Spirit of God, they are the sons of God" (14). They no longer follow the dictates of their corrupted nature or of the sinful world; they march to the beat of a spiritual Drummer, following the footsteps of their perfect Savior.
What a joy, what a privilege it is to be in Christ! Our desire, like Paul's, should therefore be to "be found in him, not having mine own righteousness, which is of the law, but that which is through the faith of Christ, the righteousness which is of God by faith" (Philippians 3:9).