180 It is written, you say, that “when we were dead in sins, He has quickened us in Christ, by Whose grace you are saved, and has raised us up together, and made us sit together in heavenly places in Christ Jesus.” I acknowledge that it is so written; but it is not written that God suffers men to sit on His right hand, but only to sit there in the Person of Christ. For He is the foundation of all, and is the head of the Church, in Whom our common nature according to the flesh has merited the right to the heavenly throne. For the flesh is honoured as having a share in Christ Who is God, and the nature of the whole human race is honoured as having a share in the flesh.
181. As we then sit in Him by fellowship in our fleshly nature, so also He, Who through the assumption of our flesh was made a curse for us (seeing that a curse could not fall upon the blessed Son of God), so, I say, He through the obedience of all will become subject in us; when the Gentile has believed, and the Jew has acknowledged Him Whom he crucified; when the Manichæan has worshipped Him, Whom he has not believed to have come in the flesh; when the Arian has confessed Him to be Almighty, Whom he has denied; when, lastly, the wisdom of God, His justice, peace, love, resurrection, is in all. Through His own works and through the manifold forms of virtues Christ will be in us in subjection to the Father. And when, with vice renounced and crime at an end, one spirit in the heart of all peoples has begun to cleave to God in all things, then will God be all and in all.
Source: On the Christian Faith (De fide) (New Advent)