"Let this mind be in you which was also in Christ Jesus, who, being in the form of God, did not consider it robbery to be equal with God, but made Himself of no reputation, taking the form of a bondservant, and coming in the likeness of men." Philippians 2:5-7
As we continue our study on, "Who is Jesus?", as we explore the wonderful realities of what is true about Him, we can't pass by Jesus being one with God. As we've considered glorious things about His aseity (self-existence) and the hypostatic union (being 100% God, 100% Man), indeed, the biblical teaching of homoousios is likewise truly awesome. What does homoousios mean? It's a compound Greek word. Homo is a Greek word meaning "same or identical". Ousios means "essence or substance". Our confession rightly states, Jesus is "of one substance and equal with the Father" (Westminster Confession of Faith, Chapter 8.2, John 1:1)
Jesus' equality with God was a focus of the Apostle Paul in his letter to the church in Philippi. We find this true, particularly in Chapter 2:6, as Paul teaches that Christ "being in the form of God, did not consider it robbery to be equal with God". In other words, Jesus wasn't trying to become God. Jesus is fully God and didn't cling to privileges that have always been His. He is the second person of the Trinity, equal with the Father. Our confession also teaches that Jesus is of "one substance, power, and eternity" with the Father and the Holy Spirit (Westminster Confession of Faith, Chapter 2.3, Matthew 3:16-17, Matthew 28:19).
This doctrine helps us in our study and understanding of the Trinity and what is referred to as the "ontological Trinity". What do we mean by this? Ontology is the study of being. So, when we consider the ontological Trinity, we are referring to the Trinity in itself, referring to God in His being without regard to His works of creation and redemption. In the Trinity, the three persons together are one being. There is a unity in the ontological structure of the Trinity (Deuteronomy 6:4). When we speak of the "economic Trinity", on the other hand, we distinguish the activity of God and roles of the three persons in the Godhead with regard to creation and redemption. Simply put, the Father sent the Son. The Son came and accomplished our redemption. The Holy Spirit applies that redemption to us.
It's true that the church in history has taken a strong stand in defense of homoousios, and rightly so. This defense was needed as heretical views were promoted. One of those views was homoiousios. Homoi means "similar." This view teaches that Jesus is superior to human beings but not equal to the Father. He is of a similar substance, not the same substance, as the Father. The other related view is heteroousios. Clearly, heteroousios is an even further departure from the truth. It states that Jesus is of an entirely different substance altogether.
A man named, Arius, who lived in the fourth century AD, held to the heteroousios view. Arius wrestled with Christ's sonship in the New Testament and went too far. This was evident in his questioning the deity of Christ. Arius claimed that the Father begat the Son as His first act of creation. However, the early church rightly understood that if the Son is not fully God, He cannot truly mediate salvation to us. Standing on Scripture, such as John 1:1-18, the church affirmed the full deity of Christ and settled the question at the Council of Nicea in 325 AD.
Now, we aren't blind to the reality that followers of Arius have continued to spout the same false claims to this very day. We see them in many places, with many faces, including the Mormons, Jehovah's Witnesses, etc. Therefore, God's people must continue to boldly confess the truth about Christ as revealed in the Bible. One of the ways we do so is by corporately confessing the creed that was written by the Council of Nicea, the creed that has been confessed in the church throughout the generations since, proclaiming Jesus Christ to be of one substance with the Father. Begotten, not created or made. He is very God of very God. We wholeheartedly confess this truth, as we say:
"And in one Lord Jesus Christ, the only-begotten Son of God, begotten of his Father before all worlds, God of God, Light of Light, very God of very God, begotten, not made, being of one substance with the Father; by whom all things were made;" (portion of the Nicene Creed)
Praise God for what He has revealed to us about our Lord and Savior in His being! Praise Him that Jesus isn't homoi or hetero, but truly is of one substance and equal with the Father and the Holy Spirit- one God in three persons from all eternity, to all eternity. May this grow our knowledge, awe, and wonder. May we be faithful to defend and confess this! Amen.