In considering the ways in which the persons of the Trinity operate in the sacraments, we need to be clear on how the doctrine of the Trinity has led the church to understand the works of our three-personed God. We cannot come to clear biblical and theological conclusions on this matter in isolation from the wider context.
The Works of the Trinity Are Indivisible
All three persons work together in all that God does. This was a basic principle at the heart of Augustine’s theology, but it was also held by Eastern Trinitarian theologians such as the Cappadocians, and it is a central part of Trinitarian belief. It follows from the fact that God is one undivided being. No one Trinitarian person is less than the whole God, nor is the whole God greater than any one person. Hence, all three mutually indwell one another in the unity of God’s being. Any notion that the Son, say, does things in which the Father and the Holy Spirit are not also directly involved would tear apart the unity of the Trinity. The term role, which has recently come into vogue in some quarters when speaking about the works of the persons of the Trinity, seems to lead in this direction, implying that each person takes on different activities from the others.
The Trinity’s undivided harmony is seen clearly in Scripture. All three persons were integrally active in creation. God created the heavens and the earth, the Spirit of God brooded over the waters, while the Word of God brought all things into existence (Gen. 1:1–5; John 1:3). In the incarnation, the Son was conceived by the Holy Spirit and sent by the Father. On the cross, the Son offered Himself to the Father by the Spirit (Heb. 9:14). The Father raised Christ from the dead by the Holy Spirit (Rom. 8:10–11), and so on.
Each Work Is Peculiarly Attributable to One Trinitarian Person
Bearing in mind the indivisibility of the Trinity in all God’s actions, each work, nevertheless, is peculiarly attributed to one of the three. While the Father sent the Son, who was conceived by the Spirit, it was only the Son who became incarnate, not the Father or the Spirit. Only the Son became man. Only the Son hung on the cross. The Holy Spirit, who proceeds from the Father and the Son, was sent by the Son, but it was only the Spirit who came at Pentecost, not the Father or the Son.
God’s Normal Pattern of Work
The three persons work according to a regular pattern in their undivided unity. In creation, providence, and grace, each work comes from the Father through the Son by the Holy Spirit. As John Calvin put it, “It is not fitting to suppress the distinction that we observe to be expressed in Scripture. It is this: to the Father is attributed the beginning of activity, and the fountain and wellspring of all things; to the Son, wisdom, counsel, and the ordered disposition of all things; but to the Spirit is assigned the power and efficacy of that activity” (Institutes 1.13.18). Elsewhere, Calvin refers to the Father as the first cause of all things, the Son as His eternal wisdom, and the Holy Spirit as His power diffused through all things (Calvin’s 1545 Catechism, 19). Since Paul usually reserves the word theos (God) for the Father, Calvin’s claim is borne out by passages such as Galatians 4:4–6: “But when the fullness of time had come, God [the Father] sent forth his Son . . . and, because you are sons, God [the Father] has sent the Spirit of his Son into our hearts.” It is evident, too, in the baptismal formula “in the [one] name of the Father, the Son, and the Holy Spirit” (Matt. 28:19).
From Our Side There Is a Reverse Order
In our experience, the pattern moves in the opposite direction. Paul states, “for through him [Christ, the Son] we . . . have access in [or by] one Spirit to the Father” (Eph. 2:18). The Holy Spirit grants us faith and enables us through the exclusive mediation of Christ, the Son, to have access to the Father. The Christian life is inherently union and communion with the triune God.
The Sacraments As Divine Actions
Throughout history, God has confirmed His covenant promises by sacraments, material signs pointing to the reality of His promises. As signs, they are appropriate to the realities they represent. The sacraments are, first, signs for God — of what He does rather than what we do. Thus, in the Noahic covenant He announces, “When I bring clouds over the earth and the bow is seen in the clouds, I will remember my covenant” (Gen. 9:14–15). The Noahic sacrament, the rainbow, is a sign first for God and points us to His action. This is true for the sacrament of the tree of life in the garden of Eden and in its eschatological (end-times, ultimate) fulfillment (Gen. 2:9; 3:22–24; Rev. 22:2, 18–19); for the Passover, which commemorated deliverance from Egypt; for circumcision, which pointed to the new heart to be given in Christ; and, by extension, for the sacraments of the new covenant.
The Father sent the Son, who, in His incarnation, united human nature to Himself by the Holy Spirit. Through the Spirit He offered Himself to the Father on the cross, making atonement for the elect. The Father raised Him from the dead by the Holy Spirit, vindicating Him publicly and the elect in union with Him. The same Spirit was sent to us by the Father in the Son at Pentecost. The Spirit unites us to Christ through faith, which He freely gives us. Jesus saw His impending death and resurrection as His baptism (Luke 12:49–50), fulfilling the baptism He received at the Jordan. In uniting us to Christ through faith, the Spirit is giving us to share in Christ’s baptism, baptizing us into one body (1 Cor. 12:13).
The regenerating work of the Spirit results in faith in the elect, and through faith, the elect are united to Christ the Son by the Holy Spirit. This union with Christ in His death and resurrection is mirrored in the sacramental symbolism of baptism.
Our regeneration is seen in the New Testament as a resurrection in union with Christ (2 Cor. 5:17). Baptism corresponds to this as the outward and material sign of this stupendous and enveloping reality. According to The Westminster Confession of Faith, it is a sign and seal of our union with Christ from regeneration to final resurrection. It exhibits this great transformation. Moreover, this union exhibited in baptism is conveyed by the Holy Spirit to His elect people in God’s own time (28.1, 6).
In baptism, the whole panorama of salvation in Christ the Son is visibly portrayed, and ultimately conveyed by the Holy Spirit to His people in accordance with the eternal purpose of God the Father. Thus, we are baptized “into the [one] name of the Father, the Son, and the Holy Spirit.”
The Lord’s Supper
In the Lord’s Supper, the faithful feed on Christ, eating His flesh and drinking His blood, not corporeally, but by the Holy Spirit through faith (John 6:47–58). Hence, Paul can say that the bread we eat is the communion (koinōnia) of the body of Christ (1 Cor. 10:17–18). That this reception of Christ is through faith is evident in the Bread of Life discourse in John 6. There Jesus parallels eating and drinking with believing (John 6:28–58). Since faith is a gift of the Holy Spirit, the Spirit enables us to receive and feed on Christ (vv. 44–45, 64-65). In this we have access to the Father.
From the side of God, Christ the incarnate Son, now ascended to the right hand of the Father, gives Himself to us in the Supper. Christ sent the Spirit at Pentecost to His church to grant us faith, to enable us to live in union with Him, and so to feed upon Him in the sacrament.
For our part, through faith we feed on Christ by the Holy Spirit. This, as Calvin argued, does not happen because the bread and wine possess any intrinsic worth or because Christ is brought down to us. Rather, the Spirit — as God — unites that which is separated by a great distance. In doing so, by His own transcendent power He enables us to ascend to feed on the ascended Christ.