As stated in the first blog post regarding soteriology, the “in Christ” motif is primarily concerned with soteriology. Though “in Christ” will relate to other systematic categories, salvation and sanctification nuances far outweigh the evidences presented. A plethora of other soteriological elements are involved with the concept of “in Christ” Redemption as the forgiveness of sins
More often than not, the description of redemption is portrayed or explained along with the idea of “purchasing back” or a ransom. However, the two passages describing the redemption of sinners with “union with Christ,” the idea of ransom is not clearly brought to the forefront. Rather, redemption, in both cases, is further refined to mean “the forgiveness of our trespasses.”
In him we have redemption through his blood, the forgiveness of our trespasses" (Eph 1:7)
"in whom we have redemption, the forgiveness of sins (Col 1:14)
Though redemption may have the idea of releasing or setting free inherent in the lexical meaning, "forgiveness of sins" provides further refinement to the meaning of redemption and "in Christ."
Reconciliation with God
With the plague of sin, a benefit of salvation is bringing sinners into relationship with the triune God. One of the clearest descriptions of sin in the New Testament delineates the deadness of man (Eph 2:1–3). Following this description of man, God is raising the dead sinner to new life with Christ (Eph 2:5–7).
...even when we were dead in our trespasses, [God] made us alive together with Christ—by grace you have been saved—and raised us up with him and seated us with him in the heavenly places in Christ Jesus. Eph 2:5–6
When God raised us with Christ, he seated us with himself through our union with Christ (Eph 2:6).
God is the primary reconciler. He has called us into fellowship with his Son (1 Cor 1:9). Moreover, through means of Christ, he is reconciling the world to Himself (2 Cor 5:18–19). God is using Christ as the ultimate agent to reconcile sinners to Himself.
All this is from God, who through Christ reconciled us to himself and gave us the ministry of reconciliation; that is, in Christ, God was reconciling the world to himself, no counting the trespasses against them, and entrusting to us the message of reconciliation. 2 Cor 5:18–19
Recipients of Grace
Grace is a wonderful blessing from God. Without grace, salvation is impossible. However, those united with Christ are direct recipients of God’s grace. Paul begins the letter to the Ephesians by describing the electing purposes of the Father and His adoption of men. The chief end of God’s electing purposes are to have men “praise his glorious grace” (Eph 1:6). The following statement provides an addendum to the grace, which we praise. “With which he has blessed us in the Beloved” (Eph 1:6). This grace is blessing us through our union with the Beloved. Moreover, Paul continually gives thanks to the Corinthian church “because of the grace of God that was given you in Christ Jesus” (1 Cor 1:4).
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With the completion of a four part series related to soteriology, Union with Christ and the "in-Christ" themes may be a better framework and more central to understanding Pauline soteriology. It is through our union with Christ that we are elected for salvation, recipients of grace, given the righteousness of God, granted a new identity, reconciled to have fellowship with God and Christ, and formulate the Church. All these blessings and privileges are through the very means of being "united to Christ."
However, the story of Pauline "in-Christ" themes does not stop there. In the coming series, we will observe the same theme of "in-Christ" and its relation to sanctification.
 Grudem, Systematic Theology, 580.