We know that the persons we used to be were nailed to the cross with Jesus. This was done, so that our sinful bodies would no longer be the slaves of sin.
The first man was named Adam, and the Scriptures tell us that he was a living person. But Jesus, who may be called the last Adam, is a life-giving spirit.
That's why only someone who has God's Spirit can understand spiritual blessings. Anyone who doesn't have God's Spirit thinks these blessings are foolish.