Shorter Catechism Q. 30. How doth the Spirit apply to us the redemption purchased by Christ? A. The Spirit applieth to us the redemption purchased by Christ, by working faith in us, and thereby uniting us to Christ in our effectual calling.
Commentary: As noted in the commentary on WSC 29, John Calvin said that Christ’s work of salvation won’t benefit us “so long as we are without Christ and separated from him.” This means that we need to be united to Jesus to receive and partake of his purchased redemption. The Scriptures refer to our union as being “in Christ,” and they compare it to the branches of a tree, the stones of a building, the various parts of a body, and the marital relationship. Furthermore, our union is compared and contrasted with our natural union with Adam. Paul says that “as in Adam all die, so also in Christ shall all be made alive (1 Cor. 15:22). The free gift of God is eternal life and it is “in Christ Jesus our Lord (Rom. 6.23).” We partake of the redemption purchased by Christ when we are “in” Christ.
To ask, therefore, how the Spirit applies to us the redemption purchased by Christ is to ask how the Spirit unites us to Christ (“…and thereby uniting us to Christ”). The answer is that he does it “by working faith in us.” Although the Spirit works faith in us, the Spirit doesn’t believe for us or in our place. We believe and we must believe to be united to Christ and thus to partake of the redemption purchased by Christ.
Here we see that union with Christ is a mutual act, involving Chrit’s work and our work. This is why the Puritans spoke about two bonds of union. The bond on Christ’s part is the Spirit, who indwells the believer, and the bond on our part is faith. In other words, Christ embraces us by his Spirit, and we embrace him by faith. This union occurs in our effectual calling or conversion, which is what we will look at in WSC 31.
Since salvation is applied via union, it cannot be separated from Christ himself. Christ doesn’t save sinners by giving them tickets to heaven so that they can stay with him or go their merry way if they so choose. Rather, Christ saves by giving himself. Redeemed sinners are united to Christ, married to him, and a part of his body. You can’t, therefore, partake of redemption without partaking of Christ and remaining in him.