Continuing our look at the Holy Trinity based on question and answer 25 of the Heidelberg Catechism, we see that while God has revealed Himself as “one, true, eternal God,” He has also revealed Himself as “three distinct persons.” For our doctrine of God to be biblical, our teaching about His nature and existence must incorporate both these truths and account for His oneness and His threeness.
That there is a threeness in God is evident from many biblical passages. Some of the most important of these are the texts in which the Father, Son, and Holy Spirit are all referred to as one God and yet distinguished from one another. The account of Jesus’ baptism in today’s passage is but one example of these texts. Also key is the Great Commission of Matthew 28:18–20, which identifies Father, Son, and Spirit with the one name of the Lord. Benedictions such as 2 Corinthians 13:14 — “The grace of the Lord Jesus Christ and the love of God and the fellowship of the Holy Spirit be with you all” — are also included in this category. This is an especially striking claim for a fiercely monotheistic Jew like Paul to make. Ancient Jews were accustomed to being blessed by the one God (Num. 6:22–27), but Paul has no problem with naming three persons when he issues the blessing. Clearly, he was not a unitarian but had a doctrine of God that was big enough to include both Jewish monotheism and a plurality in the Godhead.
That these passages all mention three persons does not mean that the Apostles believed in three gods, nor does it mean that the doctrine of the Trinity confesses belief in three gods. The doctrine of the Trinity tells us that God is both one and three. This is not a contradiction because the way in which God is one is not the same as the way in which He is three. As the church has confessed, God is one in His essence, but this essence is shared fully and equally by three distinct persons. The Father is not “more God” than the Son, and the Son is not “more God” than the Spirit. We can distinguish the three persons, but we cannot separate them, for they are the one God. This is beyond our finite minds’ ability to fully comprehend, but that is no impediment to faith. What the Word tells us about God is true: He is one in essence and three in person.
John Calvin says, “[The] Father and Son and Spirit are one God, yet the Son is not the Father, nor the Spirit the Son, but . . . they are differentiated by a peculiar quality” (Institutes 1.13.5). The Father is God, the Son is God, and the Spirit is God, but the Father is not the Son or Spirit, the Son is not the Father or Spirit, and the Spirit is not the Father or Son. This is the heart of our faith and the confession of the church throughout all ages.