WCF 8: Of Christ the Mediator

One complaint against theology is that it complicates simple matters. Do we really need doctrine if we believe the Bible and trust Jesus? Might we not lose our first love while stockpiling spiritual information? We might. And so we must resist replacing faith with mere knowledge.

But the objection that theology complicates faith is also naïve. In no other worthy endeavor does it make sense to reject deep and intimate knowledge in favor of a primitive attachment to an idea. Love should be fed by knowledge. Faith in Jesus must be child-like (Matt. 18:1–4) but not childish. We should press on, leaving behind “the elementary doctrine of Christ and go on to maturity” (Heb. 6:1). Faith can be as simple as “Jesus loves me.” But it should want to know more of how Christ the mediator loves sinners, even when that knowledge is intricate.

The work of a mediator implies estrangement and disagreement. In our natural alienation with God (Rom. 5:10) only Jesus can make us pleasing in his sight. How he does so can be summarized in four ways.

Christ’s Calling (8.1)

The triune God eternally appointed the Son to be the mediator of God’s people (Heb. 5:5). Scripture uses several models to explain Jesus’ mediatorial calling. Christ is called to be our prophet, priest, king. These Old Testament offices provided categories that Jesus filled up. Our spiritual ignorance requires a true prophet to faithfully reveal a just and loving God. Our sin requires a guiltless priest to offer sacrifices appeasing God’s just wrath against us. Our weakness requires a strong and good king to govern us and overcome our “enemies by his almighty power and wisdom.”

Jesus is also called to be the Head and Savior of the church, the Heir of all things (Heb. 1:2), and Judge of the world. The church is God’s flock. But it has wandered from the fold and needs a good shepherd who will always act in our best interests. One day, Christ the rightful king will return to reclaim from the usurping devil all that is rightfully his and punish all his enemies.

Although God’s people are united to the Mediator eternally by election, in time he executes the purposes of election through redemption, calling, justification, sanctification, and glorification (Rom. 8:29–30) to actually cure our disease of sin and make us God’s friends. To do the work of mediator God had to become a man.

Christ’s Incarnation (8.2–3, 7)

How Christ would mediate between God and man is the most beautiful of all mysteries—eternal God became human (1 Tim. 3:16). Christ isn’t a creature. He is “very and eternal God, of one substance and equal with the Father.” Yet, without giving up his deity he took on a real human nature, including our infirmities, excluding our sin. The Holy Spirit “came upon” and “overshadowed” Mary (Luke 1:35) so that the child she birthed was truly her son and God’s Son; God in real human flesh. Jesus’ human nature is perfect, “sanctified and anointed” by the Spirit. He is the ideal human. By his treasury of wisdom and knowledge, grace and truth, Jesus is “thoroughly furnished to execute the office of a mediator.”

The historic church has summarized the result of the incarnation like this: Jesus Christ is one person with two natures. In him “two whole, perfect, and distinct natures, the Godhead and the manhood, were inseparably joined together in one person, without conversion, composition, or confusion.” Jesus’ two natures didn’t blend into one, making him no longer human or divine but another sort of being altogether. His divinity was not humanized nor his humanity deified. As Jesus mediates for our sin he “acts according to both natures, by each nature doing that which is proper to itself.” Sometimes we witness more plainly Jesus’ manhood (John 11:35); sometimes his godhead (John 2:25). But at all times his actions are those of a single, unified person, our Savior.

And what do we believe about his actions?

Christ’s Work (8.4)

To mediate for us Jesus “was made under the law” (see Gal. 4:4). That means, as a human he was bound to keep the law as all humans are. But unlike the rest of us, and despite tremendous opposition and temptation, Jesus actually kept the law. This is Jesus’ active obedience. 

Christ not only obeyed for us he also suffered for us—his passive obedience. His whole journey to the cross was suffering in body and soul. The power of death worked on him even before he died. But he did also die—not just any death but a death of judgment, on a Roman cross as a vile criminal. Jesus’ enemies thought they had succeeded. For three days his body was in the tomb. The second Adam was receiving the wages of our sin. When ordinary humans die their bodies decompose. Death wins, at least for a time.

But possessing “the power of an indestructible life” (Heb. 7:16), Christ’s body did not decay. As promised God raised him from the dead, renewed his body, and received him again to his heavenly throne. There Christ continues to mediate for us, interceding for us by the merits of his perfect life and sacrificial death. His mediation is not presently evident to all. But when Christ returns in judgment everyone will witness his complete redemption of the elect (Rev. 1:7).

In the meantime his mediation is achieving powerful effects.

Christ’s Benefits (8.5–6, 8)

God’s justice both demands obedience to his holy will and inflicts punishment for lawbreakers. So in two ways Jesus’ mediation answers the claims of God’s justice that was against us. First, “By his perfect obedience” Jesus keeps the law for us. Second, by the “sacrifice of himself” Jesus pays the full penalty of our disobedience. Christ purchases both reconciliation and “an everlasting inheritance in the kingdom of heaven” for the elect. Because of Jesus believers have the forgiveness of sins and the gift of eternal life.

This is true also for those who lived before Jesus’ earthly ministry. What Jesus did “when the fullness of time had come” (Gal. 4:4) was truly efficacious; Christ’s death and resurrection defeated death and Satan and reopened the way to paradise (Col. 2:9–15). But Jesus’ earthly ministry didn’t begin God’s gracious relationship with his chosen people. As a man can love a woman before their marriage ceremony, so God has always loved his elect, even before he definitively demonstrated his devotion at the cross. So even before Christ’s incarnation God’s chosen ones were led by the Spirit to trust in the Mediator which the law and gospel had been revealing since the start.

As Mediator Christ didn’t merely purchase redemption; his Spirit also applies his benefits for the salvation of his people. He intercedes for us, authoritatively praying for our success. He enlightens our minds to the glory of grace. He persuades us to believe and obey him. And he frustrates our enemies.

Scripture’s teaching about Christ the mediator should comfort us; no one else can deliver us from our sin, shepherd us through all of life’s dangers, and bring us safely to the new heaven and earth. Christ the Savior is worthy of our trust! And because he is our Lord he is also worthy of our complete obedience.

William Boekestein pastors Immanuel Fellowship Church in Kalamazoo, Michigan. He has authored numerous books including, with Joel Beeke, Contending for the Faith: The Story of The Westminster Assembly.