When the Catechism introduces us to our Savior’s divine nature it describes Him as “the eternal Son of God.” In other words, it identifies Him with an attribute of God (“eternality”) and then identifies Him according to His distinct personal subsistence within the Godhead (“Son of God”). This description is rooted in Trinitarian categories. Both His unity with the divine essence and attributes are assumed, as well as His unique personal distinction within the divine essence. It is this latter subject, the distinct personal identity of the Son, which compels us to contemplate the doctrine of eternal generation.

I recently had the privilege of examining two theological students in Systematic Theology from the floor of Presbytery.  In the Presbyterian church, one of the highest callings of the Presbytery is licensing and ordaining men to the Gospel ministry.  A large part of this process involves subjecting candidates to several rounds of oral examination. In both of the examinations I gave, I asked the important question “what is eternal generation?”  In both cases, I could feel a bit of heartburn coming from examinee due to the question. And to be completely honest I felt a bit of heartburn for them as well, for how can mere creatures like us be expected to define what goes on in the life of the Trinity?  Or as Isaiah 53:8 says, “who shall declare His generation?”

Picking up where we left off in our last installment on Christology, we find that the middle section of Larger Catechism 36 assumes an understanding of this doctrine, while also providing us with a general outline of what it means in relation to Christ’s mediation.  Far from seeking to explain what only God the Father and God the Son know in themselves, the catechism describes the general contours of this doctrine so that we might find confidence in our Savior’s identity:

Q36: Who is the Mediator of the covenant of grace?

A36: The only Mediator of the covenant of grace is the Lord Jesus Christ, who, being the eternal Son of God, of one substance and equal with the Father, in the fulness of time became man, and so was and continues to be God and man, in two entire distinct natures, and one person, forever.

After introducing us to our need for a Mediator, as well as the name of God’s appointed Mediator, the Westminster divines now point us to the glory of His divine nature.  Jesus Christ is identified as being both the eternal Son of God and of equal substance with the Father. Each of these statements are deeply theological descriptions of the meaning and implications of His eternal generation.  As we will see, this reality not only uniquely qualifies Jesus to be our Mediator since He is God Himself, but the inter-Trinitarian relationship of the Father and the Son also unfolds to us the glory that is now ours as adopted sons.

The Eternal Son of God

When the Catechism introduces us to our Savior’s divine nature it describes Him as “the eternal Son of God.”  In other words, it identifies Him with an attribute of God (“eternality”) and then identifies Him according to His distinct personal subsistence within the Godhead (“Son of God”).  This description is rooted in Trinitarian categories. Both His unity with the divine essence and attributes are assumed, as well as His unique personal distinction within the divine essence.  It is this latter subject, the distinct personal identity of the Son, which compels us to contemplate the doctrine of eternal generation.

When we think about what distinguishes the persons of the Trinity from one another, theologians normally speak of these distinctions as “incommunicable properties”; or properties that are unique to each divine person.  When it comes to the incommunicable property of God the Son, His eternal generation is what identifies Him as the Son and distinguishes Him from the Father and the Spirit.

Question 10 of the Larger Catechism teaches us that “[i]t is proper to the Father to beget the Son, and to the Son to be begotten of the Father.”  In other words, for the Son to be “begotten” of the Father is for the Son to be eternally generated by the Father. Orthodox theologians have historically ascertained this from the very title “Son” itself. Sons, by definition, are generated by their fathers.  This is different then the concept of creation. The concept of creation implies the making of something external to one’s being, whereas generation implies something either internal to one’s being, or originating from one’s internal being. For example, a man may create a wooden figurine from objects and tools external to Himself, but he generates his son from properties inside of himself, or identical to himself in some way.  This is why the Nicene Creed says that the Son is “begotten not made.” The Son is not a creature, but a generation of the Father.

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