This is the doctrine of the incarnation, that God himself came. Jesus Christ is fully God and fully man; he is one divine-human person in two natures which are united in his personal being without mixture, confusion, separation, or division. This is who Jesus is, fully God and fully man. He is man that he might sympathise with us, be made weak like us, and suffer death, and He is God that his death would pay for the sins of all mankind!