Indwelling by Christ
Not only are believers in Christ, he is in them, and “the hope of glory” for the church is “Christ in you” (Col. 1:27). Such union, then, is inherently vital. Christ indwelling by the Spirit is the very life of the believer: “I no longer live, but Christ lives in me” (Gal. 2:20); “your life is hid with Christ in God” (Col. 3:4).
Richard Gaffin, By Faith, Not by Sight: Paul and the Order of Salvation (Paternoster, 2006), 39.