“For the death he died he died to sin, once for all, but the life he lives he lives to God. So you also must consider yourselves dead to sin and alive to God in Christ Jesus.” -Romans 6:10–11
Paul now applies to the present purpose of his letter his argument that we are in union with Christ in both death and resurrection through faith as signified by our baptism.
Christ destroyed death for us by his own death—or as the theologian, John Owen described it, he accomplished the death of Death—but now lives unto God (in the Heavenlies, reigning at the Father’s right hand) because he was resurrected. So you also, says Paul, must live your lives in this way—dead to sin and alive to God in (union with) Christ Jesus.
We who are in Christ must consider (λογίζομαι = reckon or take into account by reasoning) ourselves dead to sin. While this is true in the spiritual sense of our being, true in our standing before God presently, it is a conscientious decision that must be made each day we still live in the flesh. Simultaneously, we must consider that we have also been resurrected in Christ (though it is yet to be accomplished in our flesh) and therefore alive to God.
As Christ lives to God reigning at his right hand in the celestial realm (Heaven), we too must live to God reigning in our terrestrial realm, (Earth) as God’s viceroys (Cf. Matthew 28:18-20).