[1Jo 4:1-2, 4 KJV] 1 Beloved, believe not every spirit, but try the spirits whether they are of God: because many false prophets are gone out into the world. 2 Hereby know ye the Spirit of God: Every spirit that confesseth that Jesus Christ is come in the flesh is of God: ... 4 Ye are of God, little children, and have overcome them: because greater is he that is in you, than he that is in the world.

Has Jesus Christ come in your flesh? Can you honestly concede (confess) he is in you?

[Col 1:27 KJV] 27 To whom God would make known what [is] the riches of the glory of this mystery among the Gentiles; which is Christ in you, the hope of glory:

Or are you of a carnal mind and think he is or was flesh?

[Rom 8:6-9 KJV] 6 For to be carnally minded [is] death; but to be spiritually minded [is] life and peace. 7 Because the carnal mind [is] enmity against God: for it is not subject to the law of God, neither indeed can be. 8 So then they that are in the flesh cannot please God. 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.