Often when discussing the differences between Oneness and Trinitarian theologies the primary argument revolves around the relationship between the Son of God and the Father. Trinitarians ask questions such as:
Who was manifest in the flesh, the Father or the Son? When the scripture says, "He is BEFORE all things" (Col.1:17) is the scripture speaking of the Father or the Son? Heb.1:10 says, "And, Thou, LORD, in the beginning hast laid the foundation of the earth; and the heavens are the works of thine hands". Is this verse speaking of the Father or the Son? Is "the Son of the Father" in 2 John 3 "God"? Is He the Father?
These questions are based on one presupposition: The "Father" and the "Son" are words describing eternal relationships between persons of the Godhead. Arguing from this perspective one falls into the logical trap of:
The Son is not the Father.
The Son is God.
The Father is God.
Therefore, the Son and the Father both are God.
From there the only explanation historic Christianity has come up with is the Trinity which claims that God exists in three persons who are co-equal and co-eternal and have existed from eternity in relationship with each other. A typical Oneness rebuttal asserts that the Son is the Father, which is believed to be logically necessary if both the Son and Father are God but are not two different persons.
This explanation is faulty because it doesn't explain the biblical usage of the terms Father and Son. It is obvious that the scripture meant something by the terms Father and Son. What does it mean then? If the terms are to be held coherent then there must be a distinction between the Father and Son. However, assuming from the outset that the distinction is a distinction of "persons" is a fallacy.