What does Romans 8:10 mean by 'the body is dead because of sin' and 'the Spirit is life because of righteousness'?
Romans 8:10 contrasts the old Adam with new life in Christ. The body is dead because of sin, referring to the old Adam. But the Spirit is life because of righteousness. Being in Christ identifies the believer with His death, burial, and resurrection, so the believer rises to new life.
Les explains that Romans 8:10 follows the same concept of identification with Christ. He points to Jesus' words about a seed: unless it is put into the ground and buried, it never reproduces, but once buried it brings new life. Jesus was referring to His coming death, burial, and resurrection. Until that took place, these Greeks/Gentiles could not be an object of faith. Now in our gospel, Christ died in my place; I am identified with Him, buried with Him, and as He rose, we rose and have new life. Therefore the body is dead because of sin—the old Adam—but the Spirit is life because of righteousness.
And if Christ be in you, the body is dead because of sin; but the Spirit is life because of righteousness.