Who is who

"But you are not in the flesh but in the Spirit, if indeed the Spirit of God dwells in you. Now if anyone does not have the Spirit of Christ, he is not His." Romans 8.9

In my view, this is one of the most incisive biblical statements. It does not leave room to doubts or discussion. Those who have been possessed by the Spirit of God are so different from those who have not, just as the difference between wine and milk. The behavior of each one bears witness to who is who.