The Church belongs to Christ by virtue of the fact He purchased it.
Acts 20:28 Be on guard for yourselves and for all the flock, among which the Holy Spirit has made you overseers, to shepherd the church of God which He purchased with His own blood.
Eph. 1:22 And He put all things in subjection under His feet, and gave Him as head over all things to the church, Eph. 5:25 Husbands, love your wives, just as Christ also loved the church and gave Himself up for her;
I Cor. 6:20 For you have been bought with a price: therefore glorify God in your body.
II Peter 2:1 But false prophets also arose among the people, just as there will also be false teachers among you, who will secretly introduce destructive heresies, even denying the Master who bought them, bringing swift destruction upon themselves.