That can only mean there are many, many people who think they are Christians but are not.
Rom 8:6 For to be carnally minded is death; but to be spiritually minded is life and peace.
Rom 8:7 Because the carnal mind is enmity against God: for it is not subject to the law of God, neither indeed can be.
Rom 8:8 So then they that are in the flesh cannot please God.
Rom 8:9 But ye are not in the flesh, but in the Spirit, if so be that the Spirit of God dwell in you. Now if any man have not the Spirit of Christ, he is none of his.
Rom 8:10 And if Christ be in you, the body is dead because of sin; but the Spirit is life because of righteousness.
Rom 8:11 But if the Spirit of him that raised up Jesus from the dead dwell in you, he that raised up Christ from the dead shall also quicken your mortal bodies by his Spirit that dwelleth in you.
This one will probably bring some discussion also; but here goes...
The one recurring theme is the Spirit of God dwelling in us.
Act 8:14 Now when the apostles which were at Jerusalem heard that Samaria had received the word of God, they sent unto them Peter and John:
Act 8:15 Who, when they were come down, prayed for them, that they might receive the Holy Ghost:
Act 8:16 (For as yet he was fallen upon none of them: only they were baptized in the name of the Lord Jesus.)
Act 8:17 Then laid they their hands on them, and they received the Holy Ghost.
Act 8:18 And when Simon saw that through laying on of the apostles' hands the Holy Ghost was given, he offered them money,
The Holy Spirit is only given by the laying on of hands of one who has the Spirit. So there must be an unbroken chain from Pentecost, 31 AD until the present and the one who baptizes must have the Spirit and lay hands on the one baptized and ask that the Spirit be given to that person.