The Roots Are in the Old Testament

A fair question: if this is really in the Hebrew Bible, why have most of us never heard it?
The Old Testament roots of the two-powers doctrine have been the subject of doctoral-level work. This is not a popular-level hunch. It is the technical literature.
And the raw material is not hidden. Yahweh appears to Abraham at Mamre as one of three men, and is fed. The angel of the LORD speaks from the bush and then says "I am the God of your father." Gideon meets the angel of the LORD, realises what has happened, and expects to die. Manoah reaches the same conclusion.
In every case a figure who is called an angel or a man speaks as God, is treated as God, and accepts what only God may accept.
Scripture links:
- Genesis 18:1-2 - "the LORD appeared to him by the oaks of Mamre."
- Exodus 3:2-6 - "I am the God of your father."
- Judges 6:11-24 - "Alas, O Lord GOD! For now I have seen the angel of the LORD face to face."
- Joshua 5:13-15 - "Take off your sandals, for the place where you are standing is holy."
The pattern was there long before anyone needed it.