The biblical doctrine of the Trinity—namely, that the one, true, living, God exists eternally in three, distinct persons: the Father, the Son, and the Holy Spirit. The identity of who the Son is strikes at the very heart of the Gospel. We cannot know and worship the Father in spirit and truth unless we come to him through his eternal Son, the Son of God the Father, and by their eternal Spirit, the Spirit of God the Father and the Spirit of God the Son.