Perhaps one of the most profound passages of scripture that affirms the indivisibility of God is found in Hebrews 1:3 - Who being the brightness of his glory, and the express image of his person, and upholding all things by the word of his power, when he had by himself purged our sins, sat down on the right hand of the Majesty on high; KJV
The inspired writer asserts very clearly that Jesus is the express image of His person. Whilst the incarnation of Christ is a mystery in that it is supernatural and miraculous in nature, yet the identity of the mighty God in Christ is clearly proclaimed.
Obviously, it is impossible to exhaust the knowledge of God or have a complete comprehension of the Infinite Creator through our finite minds. However, the understanding that there is only one God, or being, in the Godhead is fundamental to not only our beliefs but to what the Bible emphatically claims.
It is well documented that the majority of the Church prior to the Council of Nicea in the 4th Century believed that there was only one in the Godhead who was revealed in three roles of Father, Son and Holy Spirit in the New Testament. The Athanasian teaching of a triune God though rejected by many believers at the time was accepted as dogma under the Roman Emperor Constantine along with other fallacious teachings that still endure in the Roman Church today.
Caution must be taken in using human terms or attributes to describe our limitless God, yet the King James translators clearly utilises the terminology in Hebrews 1:3 that the person of God is perceived through the image of Jesus Christ. There is only one person and one image of that person, just as we, as individual beings are one person and have one image. Though our existence may consist of a tripartite component of; spirit, soul and body, yet we don’t say that there are three of us. If someone claims to be more than one person, we would suggest checking them into a mental health service. Neither do we endorse any absurd ideas that though we are married or part of a community that somehow, we consider our combined relationship as one individual self-conscious being together with our spouse or others in our close relationships. At the very core of our existence is the fundamental idea of our indivisibility and oneness as autonomous creatures.
There’s no one else exactly like us. Despite someone who may look so similar to another, like an identical twin who shares strikingly similar features, down to their DNA, yet it would be totally absurd to believe they are one being or person. Genesis 1:27 tells us that man was created in the image of God. I propose that one of our main attributes that is based on God’s image is his uniqueness and absolute oneness as unequivocally stated in God’s Holy Word.