The word “homoousious” (Greek: ὁμοούσιος) is a technical theological term that was used in early Christian doctrinal debates about the nature of the Trinity. It comes from the Greek words homos, meaning “same,” and ousia, meaning “essence” or “substance.” The basic meaning of homoousious is “of the same essence” or “of the same substance.”
In the 4th century, there was a major debate within the early Christian church about whether God the Father and Jesus Christ the Son were of the same essence/substance or not. This became known as the Arian controversy, after the priest Arius who denied that the Son was fully divine. Arius taught that the Son was created by the Father, and therefore was not eternal or equal with Him.
The Council of Nicea in 325 AD rejected Arianism and adopted the term homoousious to describe the relationship between the Father and the Son. By stating that the Son is homoousious with the Father, the council affirmed that Jesus Christ shares the same divine nature as God the Father, that He is equally and eternally God.
The concept of homoousious affirms an ontological equality between the persons of the Trinity – it means that Father, Son and Holy Spirit all share the same divine being or essence. There is only one divine nature or ousia, which is common to all three persons of the Godhead. Although they are distinct persons, they are all made of the same “stuff” and are equal in power, glory, eternality, and so on. Their unity of essence allows for the diversity of persons within the Godhead.
So in summary, homoousious means “of the same essence/substance”, and was a theologically loaded term used to defend the full divinity of Christ and uphold the doctrine of the Trinity at a vital point in church history. This established orthodox teaching said that God is Three-in-One – Father, Son and Spirit are distinct yet completely equal in their shared divine nature.
The contents of the Bible relevant to understanding the meaning and significance of homoousious in early Trinitarian debates includes the following:
1. New Testament passages equating Christ with God, implying shared divine attributes:
– John 1:1 – “In the beginning was the Word, and the Word was with God, and the Word was God.”
– John 10:30 – “I and the Father are one.”
– Philippians 2:6 – Christ Jesus, “though he was in the form of God, did not count equality with God a thing to be grasped.”
– Colossians 2:9 – “In him the whole fullness of deity dwells bodily.”
– Hebrews 1:3 – Christ is “the exact imprint of God’s nature.”
2. Christ’s statements indicating eternal co-existence with the Father:
– John 8:58 – “Truly, truly, I say to you, before Abraham was, I am.”
– John 17:5 – “And now, Father, glorify me in your own presence with the glory that I had with you before the world existed.”
– Christ references to the Father sending him also imply pre-existence (John 6:38; 8:18).
3. New Testament references to the deity of the Holy Spirit, also implying shared divine attributes:
– Acts 5:3-4 – Lying to the Holy Spirit equated with lying to God.
– 2 Corinthians 3:17-18 – The Lord (ie. Holy Spirit) identified with Yahweh of the Old Testament.
– 1 Corinthians 2:10-11 – The Spirit knows the mind of God comprehensively.
4. Baptismal formula equates the three persons – Matthew 28:19:
– “baptizing them in the name of the Father and of the Son and of the Holy Spirit.”
5. Benediction showing unity – 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.”
6. 1 Corinthians 12:4-6 – Unity of Spirit, Lord (Christ) and God (the Father).
7. Ephesians 4:4-6 – One Spirit, Lord and Father over all.
By bringing these types of verses together, the case is made that according to the Bible, Father, Son and Spirit equally share the divine name, attributes, glory and power. While personal distinctions clearly exist between the persons, the Godhead is united in essence/substance.
In addition, the Bible contains a number of explicit monotheistic statements which set biblical religion apart from polytheistic systems:
– Deuteronomy 6:4 – “Hear O Israel: The Lord our God, the Lord is one.”
– 1 Corinthians 8:6 – “For us there is one God, the Father…and one Lord, Jesus Christ…”
– Ephesians 4:6 – “one God and Father of all, who is over all…”
– 1 Timothy 2:5 – “For there is one God…”
If Christ and the Spirit are fully divine, but there is only one God, then oneness of essence logically follows. The doctrine of homoousious allowed the early church to reconcile monotheism with Christ’s divinity.
In the 4th century debates, homoousious contrasted with the Arian term homoiousios, referring to Christ being of “like” essence or substance to the Father, but not the same essence. Dropping just the iota from homoousious changed the meaning significantly!
Homoousious enabled the orthodox position to be succinctly stated, as at the Council of Constantinople in 381:
“We believe…in one Lord Jesus Christ, the only-begotten Son of God, begotten of the Father before all worlds, Light of Light, very God of very God, begotten not made, being of one substance with the Father.”
This affirms that Christ shares the Father’s divine nature, while also being the Son who derives His existence from the Father eternally. Homoousious safeguarded this paradoxical but profoundly important doctrine.
In summary, the theological term homoousious means “of the same essence/substance”, referring to the eternal, equal, shared divine nature between the persons of the Trinity – Father, Son and Holy Spirit. Key verses in the Bible undergird this doctrine, which was crystallised in the 4th century as orthodox teaching about the triune Godhead in early church councils. This affirmed the full divinity of Christ while upholding monotheism.