We believe in one God existing in three persons: God the Father, God the Son, and God the Holy Spirit, operating in perfect harmony; who exists outside of space and time. All three form the Godhead and were present in the creation account (Let us make mankind in our image, in our likeness, so that they may rule over the fish in the sea and the birds in the sky, over the livestock and all the wild animals, and overall the creatures that move along the ground. – Genesis 1:26). Operating as one God, they each have their own function: the Father chooses those in Christ to be saved (For He chose us in Him before the creation of the world to be holy and blameless in his sight. – Ephesians 1:4), the Son redeems them (In Him we have redemption through His blood, the forgiveness of sins, in accordance with the riches of God’s grace. – Ephesians 1:7), the Holy Spirit convicts and seals them (And you also were included in Christ when you heard the message of truth, the gospel of your salvation. When you believed, you were marked in Him with a seal. – Ephesians 1:13).
While the Bible never mentions the Trinity by name, there is evidence to support the Godhead:
Jesus’ Baptism: All three were present (As soon as Jesus was baptized, he went up out of the water. At that moment heaven was opened, and he saw the Spirit of God descending like a dove and alighting on him. And a voice from heaven said, “This is my Son, whom I love, with him I am well pleased” – Matthew 3:16-17)
The Great Commission: All three were mentioned by name (Therefore go and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, and teaching them to obey everything I have commanded you. And surely I am with you always, to the very end of the age. – Matthew 28:19-20