In high school, I saw a print ad for a tire company that vividly stuck in my memory. It was the picture of a sprinter. He was coiled up at the starting blocks. His muscles were tensed and ready to explode into an all-out sprint. But on his feet were bright red high-heeled shoes. The ad’s header explained this jarring juxtaposition: “Power means nothing if it cannot be applied.” It doesn’t matter how powerful the sprinter is if that power cannot be effectively applied to the track. It is the same for our theology. It does not matter how powerful your covenant theology is if you cannot practically apply that theology to the real lives of the family, the church, and the individual. What does covenant theology do? What does our covenant theology look like when it is applied to our lives?
In applying covenant theology, we need to recognize that God covenants corporately and not simply individually. God’s covenant with Abraham was not just to Abraham but “to [his] offspring” (Gen. 15:18; 17:7). This does not remove the individual, but the individual does not simply remain an individual. Every individual is born naturally into a family and a people. Likewise, an individual believer is born supernaturally from above into a fellowship with Christ as Head. The individual Christian is part of a family; the “household of God” (Gal. 6:10; Eph. 2:19; 1 Tim. 3:15; Heb. 3:6; 10:21). Thus, the application of the covenant primarily happens in the household of God, that is, in the church. It certainly has implications for the individual and for the natural family, but it is seen primarily in the church. This means that a faith expressed solely as “just God and me” is foreign to the pages of Scripture.
We can see how the covenant is applied in the life of the church when we see the parallels between Christ as the substance and Mediator of God’s covenant blessings and the church as the recipient and instrument of God’s covenant blessings. The substance of the covenant is Christ Himself, “who has blessed us in Christ with every spiritual blessing” (Eph. 1:3). And these blessings are mediated through Christ (Eph. 1:20; 1 Tim. 2:5). The “what” and the “how” of the covenant are Christ. But where these blessings make contact with believers is in and through the church. This is where the rubber meets the road. The church is the recipient of Christ, “the fullness of him who fills all in all” (Eph. 1:23). And the church is the instrument of Christ, by which this blessing causes the church to build “itself up in love” (Eph. 4:16). In sum, the application of the covenant is when the church receives and is built up in Christ. One way we can speak about how the church receives and is built up in Christ is by what theologians call the “marks of the church.”
Usually theologians speak of three marks of the church: the Word, the sacraments, and discipline. But there is enough overlap in these that Calvin saw only two, Word and sacrament, whereas Francis Turretin limited it to the Word alone. This points to how the Word can be seen as primary in that it governs how the sacraments and discipline are administered.
Christ, as substance and Mediator, is revealed to us through the Word. Therefore, how we worship is dictated to us by the terms of God’s covenant with us as expressed in that Word. It is directed by more than just our feelings; rather, our worship must be obedient to God’s Word. Our worship must sing the Word, pray the Word, hear the Word, preach the Word, and see the Word. In this obedience to God’s Word, we renew our commitment and faithfulness to His covenant on a weekly basis.
As we think about how we receive Christ and then are built up in Christ, we come again to our being nurtured by Christ through God’s Word. It is milk to the immature and solid food to the mature (1 Cor. 3:2; Heb. 5:12). We abide in the Word (John 8:31). We keep His Word (14:23). We study the Word (5:39). It is by the Word of God’s covenant applied to us in and through Christ that we are reborn, brought to faith and repentance, purified and sanctified, and gathered and established. We are built up on the firm foundation of that Word into the “pillar and buttress of the truth” (1 Tim. 3:15).