Union with Christ

...union with Christ is union with the justified Messiah and the now Righteous One. Jesus by fact of his resurrection is the locus of righteousness and redemption (cf. 1 Cor. 1.30; 2 Cor. 5.21; Eph. 1.17) and believers are justified only because they have been united with the justified Messiah. Whereas believers formerly shared the verdict of condemnation pronounced on Adam, now they partake of the verdict of justification pronounced of Christ. The believer passes through the eschatological judgment by virtue of their association with Christ in his death and is co- quickened into the eschatological life through his resurrection. The union is symbolized through baptism but the conduit is, as always for Paul, through faith (cf. Gal. 3.26-27; Col. 2.12; Eph. 3.17). It is union with Christ in his death and resurrection that constitutes the material cause of justification.—The Saving Righteousness of God, page 56

<idle musing>
I've heard it said that if you take the phrase "in Christ" out of Paul's letters you end up with morality. In Christ is central to Paul—and the resurrection is central to being in Christ!
</idle musing>