JonC,
You said that, but here is what a real Calvinist says; JOHN MURRAY;
Union with Christ is the central truth of the whole doctrine of salvation. All to which the people of God have been predestined in the eternal election of God, all that has been secured and procured for them in the once-for-all accomplishment of redemption, all of which they become the actual partakers in the application of redemption, and all that by God’s grace they will become in the state of consummated bliss is embraced within the compass of union and communion with Christ...It is significant that the election in Christ before the foundation of the world is election unto the adoption of sons. When Paul says that the Father chose a people in Christ before the foundation of the world that they should be holy, he also adds that in love He predestinated them unto adoption through Jesus Christ (Eph 1:4-5). Apparently, election to holiness is parallel to predestination to adoption—these are two ways of expressing the same great truth. They disclose to us the different facets that belong to the Father’s election. Hence, union with Christ and adoption are complementary aspects of this amazing grace. Union with Christ reaches its zenith in adoption and adoption has its orbit in union with Christ. The people of God are “heirs of God and joint-heirs with Christ” (Rom 8:17). All things are theirs whether life or death or things present or things to come, all are theirs because they are Christ’s and Christ is God’s (1Co 3:22-23). They are united to Him in Whom are hid all the treasures of wisdom and knowledge, and they are complete in Him Who is the head of all principality and power (Col 2:3, 10).
It is out of the measureless fullness of grace and truth, of wisdom and power, of goodness and love, of righteousness and faithfulness that resides in Him that God’s people draw for all their needs in this life and for the hope of the life to come. There is no truth, therefore, more suited to impart confidence and strength, comfort and joy in the Lord than this one of union with Christ. It also promotes sanctification, not only because all sanctifying grace is derived from Christ as the crucified and exalted Redeemer, but also because the recognition of fellowship with Christ and of the high privilege it entails incites to gratitude, obedience, and devotion. Union means also communion; and communion constrains a humble, reverent, loving walk with Him Who died and rose again that He might be our Lord. “But whoso keepeth his word, in him verily is the love of God perfected: hereby know we that we are in him. He that saith he abideth in him ought himself also so to walk, even as he walked” (1Jo 2:5-6). “Abide in me, and I in you. As the branch cannot bear fruit of itself, except it abide in the vine; no more can ye, except ye abide in me” (Joh 15:4).
There is another phase of the subject of union with Christ that must not be omitted. If it were overlooked, there would be a serious defect in our understanding and appreciation of the implications of this union. These are the implications that arise from the relations of Christ to the other Persons of the Trinity and from our relations to the other Persons of the Trinity because of our union with Christ. Jesus Himself said, “I and my Father are one” (Joh 10:30). We should expect, therefore, that union with Christ would bring us into similar relation with the Father. This is exactly what our Lord Himself tells us: “If a man love me, he will keep my words: and my Father will love him, and we will come unto him, and make our abode with him” (Joh 14:23). The thought is overwhelming, but it is unmistakable: the Father, as well as Christ, comes and makes His abode with the believer!
Perhaps even more striking is another word of Jesus: “Neither pray I for these alone, but for them also which shall believe on me through their word; That they all may be one; as thou, Father, art in me, and I in thee, that they also may be one in us: that the world may believe that thou hast sent me. And the glory which thou gavest me I have given them; that they may be one, even as we are one: I in them, and thou in me, that they may be made perfect in one; and that the world may know that thou hast sent me, and hast loved them, as thou hast loved me” (Joh 17:20-23). And not only is it the Father Who is united with believers and dwells in them; Jesus tells us likewise of the indwelling of the Holy Spirit, “And I will pray the Father, and he shall give you another Comforter, that he may abide with you for ever; Even the Spirit of truth; whom the world cannot receive, because it seeth him not, neither knoweth him: but ye know him; for he dwelleth with you, and shall be in you” (Joh 14:16-17).
It is union, therefore, with the Father and with the Son and with the Holy Spirit that union with Christ draws along with it...Believers enter into the holy of holies of communion with the triune God, and they do so because they have been raised up together and made to sit together in the heavenlies in Christ Jesus (Eph 2:6). Their life is hid with Christ in God (Col 3:3). They draw nigh in full assurance of faith having their hearts sprinkled from an evil conscience and their bodies washed with pure water because Christ is not entered into holy places made with hands but into heaven itself now to appear in the presence of God for them (Heb 9:24).