Christians believe in one God but they believe he exists in three parts or ‘persons’. These are the Father, the Son and the Holy Spirit, known collectively as the Trinity.
The Trinity is first mentioned in Genesis as part of the creation story, where all three persons of the Trinity; Father, Son and Holy Spirit are present. Today it is mentioned during many Christian ceremonies and is a central belief of Christianity.
We believe in one God, the Father, the Almighty, maker of heaven and earth. … We believe in One Lord, Jesus Christ, the only Son of God … of one Being with the Father … [who] was made man … he suffered death and … he rose again. … We believe in the Holy Spirit … the giver of life, who proceeds from the Father and the Son … who has spoken through the prophets.From the Nicene Creed
Christians believe that God the Father is:
The gospel narratives reveal that God the Son came into the world in the person of Jesus, who is:
St Paul described Jesus as having “equality with God” (Philippians 2:6).
Importantly, the Gospel of John makes clear that Jesus has always been God’s son, even from before his birth:
In the beginning was the Word, and the Word was with God, and the Word was God. He was with God in the beginning. Through him all things were made; without him nothing was made that has been made.John 1:1-3
The Holy Spirit is the guiding part of the Trinity. Christians believe the Holy Spirit is:
I will ask the Father, and he will give you another advocate to help you and be with you for ever - the Spirit of truth(John 14:16-17)