The Indwelling of the Holy Spirit: A Proof of Being Christ's
Source: TTT
Romans 8:9
You, however, are controlled not by the flesh, but by the Spirit, if the Spirit of God lives in you. And if anyone does not have the Spirit of Christ, he does not belong to Christ.
1 John 4:13
By this we know that we remain in Him, and He in us: He has given us of His Spirit.