Rodney L. Smith
Hebrews 1:3, speaking of Jesus, says,
“Who being the brightness of His glory and the express image of His person, and upholding all things by the word of His power (or powerful word, NIV), when He had by Himself purged our sins, sat down at the right hand of the Majesty on high.”
This says that God, Father of the human Jesus, is a “Person” not “persons” and that Jesus is the “express image” or “exact representation” of that Person. Therefore, God is 1 person because Jesus, His exact image and “representation of His being” (NIV) is only one person. This sheds a whole lot of light on Colossians 2:9, “For in Him dwells all the fullness of the Godhead bodily,” that is, in Jesus Christ. Look also at what follows. It is the Son, Jesus, who sustains everything by His own “powerful word” (NIV). If Jesus is merely God’s Word and distinct from Him, then it would be inaccurate to say that Jesus “sustains” or upholds the universe by His word. It would rather be God the Father who sustains the cosmos by His powerful Word, if trinitarian theology were true. However, this plainly shows that the only way to correctly interpret who Christ is and who God is is to confess that they, rather He, is one and the same Person, for Jesus is the Word of God (John 1:1), and yet Jesus sovereignly sustains and supports everything by His powerful word (Hebrews 1:3).