The Incarnation of the Son of God


To “incarnate” means to “take on flesh”. In the case of Jesus Christ, it refers to the dogma that the Son of God – the second person of the Holy Trinity – assumed a human nature at his conception in the Blessed Virgin Mary. The incarnation is one of the central mysteries of the Christian faith – one that sets Christianity vastly apart from all other religions. While nearly all religions include belief in God (or gods) and some human prophet, only Christianity has a human prophet that is also God (John 1:14-18; Acts 1:18-19)!

The incarnation itself is a theological mystery. These are truths of faith that cannot not be known unless God reveals them because they surpass reason (even though they are reasonable). They are never fully comprehensible – but they are affirmable. To avoid apparent contradictions in the data (see below), theologians make important distinctions when defining mysteries, and those concerning the incarnation are very important.

Jesus is God

  • Jesus was worshiped by the Magi (Matthew 2:11) and his disciples (Matthew 14:32-33).
  • Jesus’ claimed to be God (John 8:58-59 cf. Exodus 3:14; John 10:30-33).
  • Jesus referred to as God (John 20:27-29; Titus 2:13-14; Philippians 2:5-11).
  • Jesus has divine attributes:
    • Creator (John 1:1-3; Colossians 1:15-17)
    • Forgiver of Sins (Matthew 9:1-8 cf. Mark 2:3-12)
    • Immutable (Hebrews 13:8)
    • Omnipotent (John 5:19; Philippians 3:20-21; Revelation 1:8 cf. 21:6)
    • Omnipresent (Matthew 28:20)
    • Omniscient (John 2:25, 16:30; Colossians 2:3)

 Jesus is Human

  • Jesus’ humanity became one of the first tests of orthodoxy (1 John 4:2; 2 John 7).
  • Jesus has human attributes:
    • Body: “The Word became flesh” (John 1:1). Jesus was born (Luke 2:7) and grew (Luke 2:40, 52). Jesus became tired (John 4:6), thirsty (John 19:28), and hungry (Matthew 4:2). He became physically weak (Matthew 4:11; Luke 23:26) and died (Luke 23:46). Jesus resurrected bodily (Luke 24:39; John 20).
    • Soul: “He is able to deal gently with the ignorant and wayward, since He himself is subject to weakness” (Hebrews 5:2).
      • Intellect: “Jesus increased in wisdom and in stature and in favor with God and man” (Luke 2:52). “Concerning that day or that hour, no one knows, not even the angels in heaven, nor the Son, but only the Father” (Mark 13:32).
      • Will: “I have come down from heaven, not to do my own will but the will of him who sent me” (John 6:38). Jesus prays to the Father, “Not as I will, but as you will” (Matthew 26:39).

Dogma of The Incarnation

The most important distinction in this case is between a “person” and a “nature.” Put (very) simply, a person is who something is, and a nature is what something is. Jesus is the second person of the Holy Trinity (the other two being the Father and the Holy Spirit). Prior to the incarnation, Jesus was a single person with a single nature (divinity). At the incarnation, Jesus took on an additional nature (humanity) – but he remained a single (divine) person. When we speaking of Jesus, then, there is one “who” (the divine person) and two “whats” (the divine and human natures). Then, now, and forever, Jesus is the God-Man!

Why was the incarnation important? Because it allowed Jesus to reconcile humans to God. The Catechism records four reasons Jesus incarnated:

  1. The Son of God became man to reconcile us to God by dying for our sins. (CCC 457)
    • Genesis 3:15 – God promises a savior born of woman.
    • Luke 1:26-38 – Jesus is conceived by the power of the Holy Spirit by the Virgin Mary.
    • John 1:1-18 – The Word became flesh and dwelt among us.
    • Philippians 2:5-11 – Jesus, although God, humbly took human form.
  2. The Son of God became man to show us the depth of God’s love for us. (CCC 458)
    • John 3:16-17 – God loved the world and sent his only begotten Son to save it.
    • Romans 5:8 – God’s love for us was so great that Jesus died for us while we were still sinners.
  3. The Son of God became man to show us how to be holy. (CCC 459)
    • 2 Corinthians 5:18-21 – Christ reconciled us to God so that we might become holy.
    • Hebrews 4:14-15 – Jesus was like us in every way but sin.
  4. The Son of God became man so that we might partake in His own nature. (CCC 460)
    • Galatians 4:4-5 – The Son was sent that we might become God’s adopted children.
    • 2 Peter 1:3-4 – God has called us to everlasting life and to partake of his divine nature.

No mere human could accomplish these things, but God alone couldn’t either – for God, being divine, cannot die. Jesus took on human nature so that he could accomplish what only the God-Man could accomplish.

Difficulties of The Incarnation

If this sounds confusing, that is understandable. There are several reasons for this confusion.

First, because Jesus is one “who” (the divine person) and two “whats” (the divine and human natures), his attributes are sometimes attributed to the wrong natures or are seen to conflict. What we need to always remember is that whatever pertains only to Jesus’ humanity will be finite although the attributes of his divine nature are infinite. So Jesus possess all the attributes of deity (e.g., creator, forgiver, non-changing, all-knowing, everywhere-present, almighty, etc.) and all those of humanity (e.g., body, soul, beginning, learning, growing, etc.). All of this fuss may seem silly, but it is a human attempt to reconcile what often seem to be mutually exclusive truths about Jesus.

Second – lack of precision in the way we speak of the incarnation can make things difficult. Jesus remained a divine person even though he assumed human nature. Jesus did not “change into” a human – he did not go from being God to being human. So, Jesus is one divine person with two natures (one divine and one human) – not two persons with two natures. He is truly and fully God and human – not part God and part human, not partially God and partially human. So, for example, Jesus has two intellects and two wills yet remains a single person. This also means Jesus could not act in a way contrary to divinity, for although he could operate through his human nature, he was still only a divine person (so, for example, Jesus could not sin or be ignorant of some truth).

Third, because the word “God” is often used as the title of a person and not a nature, the words “God” and “Jesus” are often used interchangeably (e.g., “Mary is the Mother of God”, or “God died on the cross”) – but not always (e.g., “For the Son of God became man so that we might become God” – Athanasius). It is always important, then, to clarify exactly how words like “God”, “divine”, “nature”, “person”, etc. are being used in order to avoid misconceptions.

Confusion from these and other areas has led to numerous heresies in the history of the Church.

Heresies of The Incarnation

At the incarnation, Jesus took on an additional nature (humanity) – but he remained a single (divine) person with a divine nature as well. Confusion from these and other areas has led to numerous heresies in the history of the Church – most of which were made in the first few centuries of the Church and dealt with by the Church Councils. See especially the Dogmatic Definition of the Council of Chalcedon (AD 451). Further, although the Catholic Church, Eastern Orthodox, and most Protestants agree on these orthodox positions, the majority of heresies arose within the Church and many were held by numerous bishops throughout history. The Bishop of Rome, however, has never been the definer or teacher of heresy.

Jesus is Divine but Not Human

One of the earliest heresies did not deny Jesus’ deity, but rather his humanity. That Jesus was a god who only seemed to be human is known as Docetism. This teaching was also believed by Gnostics, who think all matter is evil. This false teaching arose outside the Church and died out early, so it was not directly addressed by any Council but it was implicitly rejected by the teachings of the fathers and councils.

Jesus is Human but Not Divine

Many today believe that Jesus was just a good man / prophet / teacher, but was not God Almighty. An offshoot of this misguided distinction is Adoptionism / Monarchianism which teach that Jesus was a human who God adopted as his Son. This idea was condemned at the Synod of Antioch (AD 268). Socinianism was an Anabaptist belief denying Jesus’ pre-existence. Early Jewish Ebionites, modern Skeptics, Deists, Unitarians, and Jehovah’s Witnesses, all deny Jesus’ divinity – but the most famous historical expression was Arianism. A priest named Arius believed Jesus was a created being with a distinct substance from God the Father. Arianism spread throughout the Church, but was condemned at the Council of Nicaea. This is why the Nicene Creed says Jesus is “consubstantial” with the Father. The term is from the Greek “homoousias” rather than “homoiousias” – (mo = “same” vs. moi = “similar” substance). This is the origin of “It makes not one iota of difference.” 

Jesus is a Mixture of Humanity and Divinity

Several versions of this error (e.g., that  Jesus’ divine nature replaced/absorbed or completely dominated his human nature) have arisen over the centuries. Apollinarianism was a mistaken response to Arianism by Apollinaris, Bishop of Laodicea, which was condemned at the Council of Constantinople (AD 381). Eutychianism taught that Christ’s divinity dominates and overwhelms his humanity. It was condemned at the Council of Chalcedon (AD 451) along with Monophysitism which sees Jesus as a blend of the human and divine natures. (Note that this is distinct from Miapysitism – the view that Jesus’ divinity and humanity unite in a compound nature without separation, mixture, confusion, or alteration. This view is held by Chalcedonian Christians and Oriental Orthodox and can be understood in an orthodox manner. Monothelitism is the view that Jesus had a single will,  and it was condemned at the Third Council of Constantinople (AD 681).

Jesus is Two Persons in Two Natures

Nestorianism arose when Nestorius, Bishop of Constantinople, thought that Mary’s title “Mother of God” (Theotokos) implied that Jesus had only one nature. In response, Nestorius distinguished Jesus’ two natures to the point of doubling the persons. This view was condemned at the Council of Ephesus (AD 431) and Council of Constantinople (AD 553).

Jesus is an Additional God

Marcionism said Jesus is a higher God than the OT God Yahweh. Many polytheistic Eastern Religions accept Jesus’ divinity alongside numerous other deities. Today, Mormonism teaches that Jesus is an exalted man who became a god, the literal, physical offspring of Elohim and Mary.


What is important to understand about all these dogmas and their attendant heresies is not their names, but the effects such teachings have on salvation. What Jesus accomplished required him to be fully God and fully man – and if either failed, so would our redemption.