The Logic of Jesus versus the Irrationality of Oneness Theology

"Jesus answered them, 'My Father is working until now, and I am working.' This was why the Jews were seeking all the more to kill Him, because, not only was He breaking the Sabbath, but He was even calling God his own Father, making Himself equal with God." 

- John 5:17-18 

Oneness Pentecostals claim that the Son was the flesh of Jesus, which, therefore, did not exist before its creation in the womb of Mary at the Incarnation. Of course, if the Son didn't exist before that point, we must logically ask, Then whom exactly was incarnated? To have been made flesh, that Person must already have existed. But we will set aside that logical question for now. 

In the passage above, the Apostle John reports several things. First, we have the words of Jesus that both He and the Father have been working. He thus makes a distinction between Himself and the Father, refuting any claim that it was the Father who was incarnated in the Son. Then the Apostle tells us that His audience took the words of Jesus to be a claim of equality with the Father. Again, if the Oneness doctrine is correct, how can any created thing, even as exalted as a merely human Jesus, be equal to the Father? Unless, of course, we Trinitarians are correct and the Son is not just the flesh, but is eternal God in Himself!

Thus, Oneness claims are refuted by the simple question, If the Son is just flesh, and not God in Himself, then how can He be equal to the Father?