For the Gospel of John “God is the Father, Jesus the Son of the Father” (2 John 3; cp. John 5.18, 25-27, 41-44; 6.27, 43-46, 68-69; 20.16-17, 31). So it’s no surprise when Jesus identifies God as a Single Self, Divine Person, the Father, 20+ times in the Gospel of John alone!
Messianic Trinitarian Apologist Michael Brown, in his Jewish Objections to Jesus vol. 2, has to concede this simple and clear biblical fact when he writes that “Peter preached the same message emphatically, and Paul taught it clearly” [in 1Cor 8.4-6; 1Tim 2.5-6]: The one true God, our Father and Creator…” And that the Son “will in the end submit himself back to his Father ‘so that God will be all in all’” in 1 Cor. 15:27–28.
Lastly, former Trinitarian Apologist Aaron Shelenberger found that in John 8:42 “If God were your Father” can be converted to “God is the Father.” Likewise, he says, in John 17:3 “you [Father], the only true God” the phrase “the only true God” is appositional, i.e., “Father” and “the only true God” can be interchangeable in their being subject and predicate, so that we have: