Proposition # 7: John 5:18 says, “For this cause therefore the Jews were seeking all the more to kill [Jesus], because not only was he breaking the Sabbath, but he was calling God his own Father, making himself equal with God.” And at John 10:30, 38 Jesus said, “I and the Father are one” and “the Father is in me and I am in the Father.” This shows that he is with the Father in a triune God.
Response: Notice that Jesus was calling God “his own Father;” he was not claiming to be God. Paul helps us to get the proper sense of John 5:18 at Galatians 4:1 where he wrote, “the heir …is owner of all the estate.” By claiming to be God’s Son (and therefore, His heir) the Jews would have understood this as a claim to divine prerogatives (in this context, in regards to what can be done on the Sabbath). This is why they accused Jesus of “making himself equal with God.”
Unlike pagans the Jews had no concept of God becoming a human. So it is unlikely that they understood that Jesus was claiming to be God. (Such a claim would have been viewed as proof of insanity or stupidity.) Instead, they would have understood his claim figuratively, in the representative sense as discussed in Proposition # 1. For Jesus’ enemies such a claim would have been considered blasphemy.
As for Jesus’ being in the Father and the Father’s being in him and Their being one, consider Jesus’ prayer at John 17:20, 21, “I do not pray for these only but also for those who believe in me through their word, that they may all be one: even as You, Father, are in me, and I in You, that they also may be in Us.” If John 10:38 means that the Son is one person in a multiple Godhead, then John 17:20, 21 means that believers are also persons in that Godhead! Being one in these passages means being in harmony, united in thought and purpose. — Romans 15:5, 6; 1 Corinthians 1:10
But notice whom Jesus did claim to be in the context of these verses. John 10:30-36 records: [Jesus said,]
“‘I and the Father are one.’ The Jews took up stones again to stone him. Jesus answered them, ‘I have shown you many good works from the Father; for which of these do you stone me?’ The Jews answered him, ‘It is not for a good work that we stone you but for blasphemy because you, being a man, make yourself God.’ Jesus answered them, ‘…do you say of him whom the Father consecrated and sent into the world, “You are blaspheming,” because I said, “I am the Son of God”?’”
This would have been the perfect opportunity to declare himself to be God the Son, if he truly were. Did he? No, he claimed to be the Son of God!
By saying that he and the Father are one (united in thought and purpose), Jesus was claiming God’s backing for his miracles (“many good works”) which the Jews themselves had witnessed, but rejected as evidence of divine favor. As noted above it is not likely that they would have taken Jesus’ response as a claim to being God literally; rather it would have been in the representative sense.