The Doctrine of the Trinity

Q 6: How many persons are there in the Godhead?
Answer: There are three persons in the Godhead; the Father, the Son, and the Holy Ghost; and these three are one God, the same in substance, equal in power and glory.

Since God is at the center of our faith and religion, it is vital that we believe the right things about him. If we are to have fellowship with God, we need to know who he is, even if the truth seems rather mysterious. We find in Scripture that God is a personal God and that in fact he is three persons, though he is only one God, one divine being. 

The word “substance,” used in the catechism, is traditionally used interchangeably with the word “essence” to refer the undivided divine nature (think of question 4, “what is God?”). All three persons share the full divine being, all that God is, so that they are equal in power and glory. Each person of the Trinity has all the attributes of God. 

These persons are distinct, not interchangeable. They are distinguished by their personal properties. As our larger catechism explains in its tenth question, these personal properties are that only the Father begets the Son, only the Son is begotten of the Father, and only the Holy Spirit proceeds from the Father and the Son, and this has always been the case from eternity. Jesus is the only-begotten of the Father (John 1:14), and the Spirit is the Spirit of the Father (John 15:26) and of the Son (Gal. 4:6). From eternity, they have been with each other and loved each other (John 1:1, 17:5, 24). Furthermore, in history they play united but distinct roles in the work of salvation, as 1 Peter 1:1-2 describes, “To those who are elect exiles … according to the foreknowledge of God the Father, in the sanctification of the Spirit, for obedience to Jesus Christ and for sprinkling with his blood.”

Our Westminster standards take up and affirm the truths affirmed in the ancient creeds of the church, such as the Nicene and Athanasian Creeds. We recite the Nicene Creed every week in worship, and the Athanasian Creed is worth reading as well. But here is a simple summery of the doctrine of the Trinity from J. Gresham Machen:

“The New Testament is just as much opposed as the Old Testament is to the thought that there are more Gods than one. Yet the New Testament with equal clearness teaches that the Father is God and the Son is God and the Holy Spirit is God, and that these three are not three aspects of the same person but three persons standing in a truly personal relationship to one another” (The Person of Jesus, 13-14).

It is into the name of this Triune God that we are baptized. We are called to serve and entrust ourselves to this Triune God. We are called to have fellowship with the Father and the Son and the Holy Spirit, with each one particularly and being drawn by each one to the other two and to their unity as one God.