Isaiah 45:18
For thus saith the LORD that created the heavens; God himself that formed the earth and made it; he hath established it, he created it not in vain, he formed it to be inhabited: I am the LORD; and there is none else.
For thus saith the LORD that created the heavens; God himself that formed the earth and made it; he hath established it, he created it not in vain, he formed it to be inhabited: I am the LORD; and there is none else.
The Creator of heaven and earth identifies Himself as the LORD and denies any other.
This establishes the controlling biblical confession: every later passage about Father, Son, and Holy Ghost must be read without multiplying the one God.
Apostolic teaching begins with the Bible’s own insistence that God is one indivisible divine being, then reads the incarnation as that one God revealed in Christ.
Counting titles, manifestations, or relational language does not overturn the Bible’s explicit statements that God is one and alone.
Start here before discussing difficult relational texts. Establish what Scripture says plainly about how many are God.