Regardless of your denominational affiliation, one doctrine that unites all Christians against other religions is the doctrine of the trinity. Whether Protestant or Roman Catholic, all so-called Christians affirm the doctrine that we worship one God who subsists in three persons, Father, Son, and Holy Spirit. The Westminster Confession of Faith, for example, contains the following definition: “In the unity of the Godhead there be three persons, of one substance, power, and eternity: God the Father, God the Son, and God the Holy Ghost: the Father is of none, neither begotten, nor proceeding; the Son is eternally begotten of the Father; the Holy Ghost eternally proceeding from the Father and the Son” (II.iii). This statement isn’t unique but finds its roots in the Bible and has been codified in the ancient church creeds, such as in the Councils of Nicaea (325), Constantinople (381), and Chalcedon (451). Yet, as important as the doctrine of the trinity is, I often find something slightly different in our churches.
The Roman Catholic theologian, Karl Rahner (1904-84), once noted that, even though many Christians claim to be trinitarian, they don’t practice a trinitarian-shaped doctrine and liturgy. He said that if the doctrine of the trinity were to be deemed erroneous, most liturgies, Protestant or Roman Catholic, would be unaffected. Rahner expressed these sentiments in the 1960s. About twenty years later another Roman Catholic theologian, Catherine LaCugna (1952-1997) made the same observation. Despite Rahner’s call for a robust trinitarian theology and liturgy, she believed that the situation in the broader church had not changed.
I think you find this phenomenon in the broader culture—sports figures and celebrities invoke the term God when they win games and Oscars but seldom, if ever, do you hear the name of Christ. A bit closer to home, people might pray to God, but they don’t pray in the name of Christ. Or, pastors might regularly talk about the importance of Christ but hardly make reference to the Father or Spirit. In other words, Rahner’s sad analysis still rings true some sixty years later—it seems that the vast majority of the church practices a functional Unitarianism. Christians confess the doctrine of the trinity but only one member of the godhead appears in the theology and liturgy of professed trinitarians.
There are number of biblical passages that pulsate with a robust trinitarianism. Think, for example, of the Great Commission (Matt. 28:18-19). We are supposed to baptize disciples in the name of the Father, Son, and Holy Spirit. The apostle Paul makes the following statement: “Because you are sons, God has sent the Spirit of his Son into our hearts, crying ‘Abba! Father!’ (Gal. 4:6). Paul wraps our status as adopted sons in the doctrine of the trinity—the Father sends the Son and the Spirit, who enable us to cry out to God. These are just two examples, but they should cause us to ask whether our commitment to trinitarian theology is sufficiently manifest in our doctrine and liturgical practice. Do you pray to God the Father through Jesus Christ, our great high priest, in the power of the Holy Spirit (Matt. 6:8-13; John 14:6, 14; Eph. 3:12; Heb. 4:4-16; Rom. 8:26-27)? Does your commitment to the doctrine of the trinity pervade your theology? Does your preaching reflect the doctrine of the trinity? Is it so focused upon Christ that you fail to mention the Father and Spirit?
In the end, be on guard against functional Unitarianism and ensure that your commitment to the doctrine of the trinity pervades your theology, life, and worship.