The eternal communion of Father, Son, and Spirit is the grounds for our communion with him and one another. Our triune God, simple and perfect for all of eternity, has always been the one God.
“The Son is the radiance of God’s glory and the exact representation of his being, sustaining all things by his powerful word. After he had provided purification for sins, he sat down at the right hand of the Majesty in heaven.” -Hebrews 1:3