The Son is the image of the invisible God, the firstborn over all creation. (Colossians 1:15)
God is invisible. He is so distant from us that it is impossible for us to know Him on our own power. But Jesus who is God became flesh so that we could be brought near to God. Jesus is both fully man and fully God. We learned what God is like through Jesus’ interactions with people on Earth. And He died on the cross so that our relationship with God could be restored.
No one has ever seen God, but the one and only Son, who is himself God and is in closest relationship with the Father, has made him known. (John 1:18)