So then, those who are in the flesh cannot please God. 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 8.8-9
Paul knew that among the new Roman Christians, many had accepted Jesus as their Savior but not as their Lord.
In other words, they accepted the Christian faith, but had not surrendered to this faith.
Though they were able to identify with the new true Christians, they were still of the flesh.
The same has happened to most believers: they accept Jesus, but do not surrender themselves entirely to Him.
This is why they are barred from receiving the Holy Spirit.
They have been in Church for years, receive extensive knowledge of the Word, know the prophecies of God, but do not practice them.
They are children of the flesh.
In his letter to the Roman Christians, the apostle makes it clear that those who do not have the Spirit of God do not belong to Him.
They may even be faithful in Church and walk according to religious customs, but if they do not have the Spirit of the Lord Jesus Christ, they do not belong to Him.
And there is no way you can pretend to have the Holy Spirit. Your worldly tendencies will eventually be identified.
When you are sealed with the Spirit of Jesus, your thoughts, feelings and heart are one with the Lord Jesus. There is no way to fool everyone all the time.
Paul had doubts about the sincere conversion of many Romans, considering this, he said, in other words: You should not be in the flesh but in the Spirit, if indeed the Spirit of God dwells in you.
And if someone does not have the Spirit of God, this person does not belong to the Lord Jesus.
I have seen many supposed converts serving as servants, speaking as if they were full of the Spirit and behaving (in Church) as if they were our brothers…
However, at home, work, school, or on the street, they speak like idolaters, dress like nonbelievers, react like someone that is possessed and aren’t very different from the children of darkness.