Belief in the incarnation of our Lord Jesus Christ faithfully (Athanasian Creed, line 29) requires us to confess both the twoness and the oneness of Christ. The twoness of Christ involves His two natures: He is at once fully divine and fully human. True God and true Man. The oneness of Christ consists of His Person: yet Christ is not two, but one, as the Creed will go on to confess (line 34).

Lines 31 – 33 define the twoness of Christ. Theologians call this the hypostatic union—that is, the union of two natures (hypostases).

Lesson from the Creed

He is God from the essence of the Father,
    begotten before time;
    and he is human from the essence of his mother,
    born in time;
    completely God, completely human,
    with a rational soul and human flesh;
    equal to the Father as regards divinity,
    less than the Father as regards humanity.

Athanasian Creed, lines 31-33

Explanation from Scripture

The best way to handle expositing these lines of the Creed from Scripture is to go proposition by proposition. This is how we shall proceed.

He is God. The first chapter of the Gospel according to John makes this abundantly, undeniably clear: In the beginning was the Word, and the Word was with God, and the Word was God. He was in the beginning with God. All things were made through Him, and without Him nothing was made that was made … And the Word became flesh and dwelt among us (John 1:1-3, 14 NKJV). Christ, who is the Word become flesh, is Himself God, through whom all things were made.

This is confirmed by the letters of St. Paul. In Colossians 2:9, the Apostle says: For in Him dwells all the fullness of the Godhead bodily (NKJV‬‬). The fullness of Deity could not dwell in Christ’s body were He not God. And in Romans 9:5 he says explicitly: Christ came, who is over all, the eternally blessed God. Amen. (NKJV‬‬)

Likewise, in Philippians 2:6, he says that Christ was in the form of God, and did not consider it robbery to be equal with God (NKJV). Here, the Apostle bears witness to the equality of the Son with the Father.

Meanwhile, the Gospels also bear witness that Christ is God in the details of their storytelling. Matthew 1:23 states that Jesus came to be Immanuel, which is translated, “God with us” (NKJV‬‬). He would not be God-with-us unless He were actually God! Likewise, when Thomas the Apostle beheld the risen Christ, he exclaimed: My Lord and my God! (John 20:28) He confessed that Jesus is God. Jesus didn’t correct him, which He certainly would have done were He not truly God!

From the essence of the Father, begotten before time. When it says He is of the essence (or substance) of the Father, this involves both His origin (begotten of the Father) and His equality with the Father (of the same divine essence or substance).

Again, the Gospel narrative of John is incredibly helpful here. For example, in John 10:30, Christ declares: I and My Father are one (NKJV‬‬). The Father and the Son share the same divine essence.

Likewise, we see from John that the Father and Son are co-eternal. This is what the Creed means when it says He is begotten before time. Note well what Jesus says to the Jews in John 8:58: Most assuredly, I say to you, before Abraham was, I AM (NKJV‬‬). He applies the divine Name to Himself, to say that He existed long before Abraham. Moreover, in His high priestly prayer, He said: Father … You loved Me before the foundation of the world (John 17:24 NKJV). Before the foundation of the world means outside of time, in eternity. The Son is eternally begotten of the Father, and eternally loved by Him.

And he is human from the essence of his mother, born in time. Here the Creed teaches us to confess Christ’s true humanity. We see His humanity on display in that famously short passage: Jesus wept (John 11:35). Throughout the Gospel narratives, we see Jesus doing things only a human can do: He gets hungry and eats. He gets tired, and sleeps. He sweats. He suffers and He dies.

But the facts that the Creed point to that most clearly identify Jesus as fully human, are that He had a mother, and that He was born in time. As God the Son, He is eternally begotten of the Father. But as a human, He was born of a woman at a particular time.

In Galatians 4:4, St. Paul explains: But when the fullness of the time had come, God sent forth His Son, born of a woman, born under the law (NKJV‬). That He was born of a woman—the Virgin Mary—tells us that He is human, for He has a mother: a real flesh-and-blood mother. That He was born under the law tells us that He came to fulfill the Law in our place, by submitting to it in His flesh (cf. Galatians 4:5; Hebrews 5:7-8; Romans 8:3-4). Most poignantly, it says He was born when the fullness of time had come. That is, at a particular point in history which God had determined from eternity. Luke 2:1-2 specifically tells us that this was while Caesar Augustus was emperor of Rome, and when Quirinius was governing Syria.

Completely God, completely human. This must follow from all we have observed thus far. If the Word was God and became flesh (John 1:1, 14); and if the fullness of the Godhead dwells bodily in Him (Colossians 2:9)—then Christ must be at once completely God and completely human.

With a rational soul and human flesh. Thus further clarifies Christ’s true humanity, so that we don’t fall into error. Some have supposed that the two natures involve Christ having a human body and a divine soul. As if His humanity were found in His body, and His Godhead in His soul. But by clarifying that He has a rational soul, the Creed means a rational human psyche. In other words, He is fully human, body and soul. This is confirmed in Luke 2:52, where it says: And Jesus increased in wisdom and stature, and in favor with God and men (NKJV‬‬). Like any other human, Christ increased both in wisdom (His soul, His psyche—intellect and reason); and stature (the maturation of His human body). That is, as His body grew, so did His mind. This is true of humans, never of God.

Incidentally, the Incarnation does not end at His death. For the resurrected Christ invites His followers to: Behold My hands and My feet, that it is I Myself. Handle Me and see, for a spirit does not have flesh and bones as you see I have (Luke‬ ‭24‬:‭39‬ ‭NKJV‬). Likewise the Incarnation does not end at the Ascension, for again, Colossians 2:9 says: For in Him dwells all the fullness of the Godhead bodily. Notice it says dwells, not dwelt. Our ascended Lord is still completely God, completely human, with a rational soul and human flesh. This is why Scripture says: For there is one God and one Mediator between God and men, the Man Christ Jesus (1 Timothy‬ ‭2‬:‭5‬ ‭NKJV‬‬). As our Mediator, Christ is still a Man—that is, fully human. And so it must be, for the Mediator between God and humanity must be both God and human.

Equal to the Father as regards divinity, less than the Father as regards humanity. This one distinction solves the seeming conundrum presented in John’s Gospel. For again, in John 10:30, Christ says: I and My Father are one, thus declaring the equality of the Father and the Son. But in John 14:28, He says My Father is greater than I.

But there is no contradiction there. In His divinity, He is co-eternal and co-equal with the Father (and the Spirit). In His humanity, He is less than the Father. Thus we read in Hebrews: But we see Jesus, who was made a little lower than the angels, for the suffering of death (Hebrews 2:9 NKJV). As a Man, He suffers death, and was made for a time lower than the angels that He might accomplish this in His humanity. Likewise, when He prays: Take this cup away from Me; nevertheless, not what I will, but what You will (Mark‬ ‭14‬:‭36‬ ‭NKJV‬‬); this is His human soul, His human will, speaking.

That’s why Hebrews 5:8 says: though He was a Son, yet He learned obedience by the things which He suffered (NKJV‬‬). It says though He was a Son, yet He learned obedience, because eternal Sonship does not include eternal submission, for the divine will is one; Father and Son and Spirit perfectly sharing in one will. It is in His humanity where He is less than the Father, and in the flesh where His reasonable soul must submit.

This is confirmed, again, in Philippians 2:6ff, which says He was in the form of God, and equal with God, but made Himself of no reputation, by coming in the likeness of men (NKJV‬‬).

Therefore, we find again that the Creed has gotten the doctrine of Christ exactly right, according to Scripture.

This means denying the divinity of Christ is damnable heresy.

Denying the humanity of Christ is damnable heresy.

Confounding or collapsing either of the natures with or into the other is damnable heresy.

And teaching that the Son is in any regard eternally less than the Father is damnable heresy.