John 5:16-18 (LGV) 16 And because of this the Judeans were pursuing Jesus and were seeking to kill Him, because He was doing these things on a Sabbath. 17 But Jesus replied to them, “My Father is working until now, and I am working.” 18 The Judeans then increasingly sought to kill Him because not only was He breaking the Sabbath but was also calling God His own Father, making Himself equal with God!
In this passage the leaders of Israel were looking for reasons to accuse Jesus of some serious crime against the Law of Moses. Their first attempt was to accuse Him of breaking the Sabbath prohibitions against work.  In defense of Himself, Jesus said: “My Father is working until now, and I am working.” This statement was intended to show that Jesus was simply following His Father’s lead, who was actually performing the miracles when Jesus simply spoke the word of healing. Jesus was not really “working” on the Sabbath, God was.
However, His defense was immediately rejected, as they focused on the fact that He had just called God His “own Father.” They increasingly sought to kill Him for something that went far beyond breaking the Sabbath – blasphemy. John says this was because He “was also calling God His own Father, making Himself equal with God.” The little word ἴδιον (own) goes far beyond merely referring to God generically as a Father. It makes this relationship exclusive to Himself as opposed to a broader non-literal sense such as being the creator. Jesus was claiming something far beyond merely being an Israelite. Jesus was claiming a very unique relationship, the very reason for which John referred to the Son in His prologue as “the only-begotten of the Father.” The same unique father-son relationship is found in Romans 8:3,32 where Paul called Jesus God’s “own Son.” Claiming such an exclusive relationship with God was blasphemy in their view, as is proven by the following statement of John’s that Jesus was “calling God His own Father, making Himself equal with God.”
In a familial relationship of a father and a son, there is only one way that a “son” could be considered as his father’s equal. It was certainly not in rank or priority since a father precedes his son and gives existence to his son, thus outranks him. A father is only equal with a son in ontological nature. A human father has a human son, they are equally human. However, if God was exclusively Jesus Father, then in their thinking Jesus was claiming to be of the God “kind,” having the divine nature of God.
As has been stated quite a few times in the articles on this site, John wrote his Gospel and epistles after Paul’s death in order to reinforce Paul’s teaching to the Gentiles which was being perverted by proto-gnostic groups, the Nicolaitans and the followers of Cerinthus. This is important because in Paul we have the only other place where Jesus is said to be “equal with God.”
Phil.2:5-8 (LGV) 5 Have this disposition in you which [was] also in Anointed Jesus 6 who, being in the form of God, did not consider to be equal with God a prize, 7 but emptied Himself, taking the form of a slave, becoming in the likeness of men. And having been found as human in design, 8 He suppressed Himself, becoming obedient unto death, even death of a cross.
In John 5:18, “equal with God” uses the same Greek words as in Phil. 2:6. But here Paul defined what “equal with God” actually meant. Notice that His equality with God is contrasted with what He became after He “emptied Himself.” He took the form of a slave by “becoming in the likeness of men.” The word “becoming” is the same word John used in the clause, “and Logos became flesh.” To become in the likeness of men means that He was not previously in the likeness of men prior to His emptying Himself. There is no question that these are parallel concepts and that John intended to reinforce Paul’s teaching in this very passage.
It is also apparent that the Israelite leaders understood that Jesus was claiming to be literally begotten out of God. There is only one Person in the Old Testament who is said to have literally been “begotten” out of God and thus was His literal Son. In Psalm 2:7 the Messiah declares, “I will tell of the decree: The LORD said to me, ‘You are my Son; today I have begotten you’” (ESV). Also “Wisdom,” who was God’s assistant in the creation of all things, said, “When there were no depths I was brought forth, when there were no springs abounding with water. Before the mountains had been shaped, before the hills, I was brought forth, before he had made the earth with its fields, or the first of the dust of the world, … then I was beside him, like a master workman, and I was daily his delight, rejoicing before him always,” (Prov. 8:24-26,30 ESV).
However, what the Israelite leaders did not comprehend was the self-emptying which the Son of God willingly did when He “became in the likeness of men,” what John described as “and Logos became flesh.” They wanted to kill Jesus because He was obviously a human being which cannot in any sense be “equal with God” in ontological nature or any other way. That this was their thinking can be shown from a similar encounter recorded in John 10:32-33. “Jesus answered them, ‘I have shown you many good works from the Father; for which of them are you going to stone me?’ The Jews answered him, ‘It is not for a good work that we are going to stone you but for blasphemy, because you, being a man, make yourself God’.” (ESV)
Note the disparity between what Jesus actually was (ontologically) as opposed to what they supposed He was claiming to be. It is the difference between humanity and divinity. Jesus was clearly a Man. It was common knowledge that He had a mother and brothers. When they said to Him, “You, being a man, make yourself God,” as monotheists they certainly did not suppose that He was claiming to be Yahweh Himself to whom Solomon declared, “But will God indeed dwell on the earth? Behold, heaven and the highest heaven cannot contain you; how much less this house that I have built!” However, many times the Messenger of Yahweh who visited the patriarchs referred to Himself as “God” (Elohim). For example when appearing to Moses in the burning bush He said, “I am the God of your father Abraham…” For the same reason John stated in his prologue, “and Logos was God.” This was because of what Paul stated in Colossians 1:15, “He is the image of the invisible God.” The visible “image” of the invisible “God” used God’s name and titles when He appeared throughout the Old Testament in the place of God.
The leaders of Israel had a certain misconception concerning what Jesus was actually claiming. They were correct in assuming that calling God His “own Father” necessarily implied equality in ontological nature with God, that the offspring must be of the same “kind” as the parent. Yet, Jesus was clearly a Man.
Jesus then immediately claimed that He did not (currently) possess the divine nature (divinity) by quickly denying that He had the inherent power to perform the miracles. Rather, the Father was actually doing the miracles through Jesus, who merely spoke the word as the Father communicated to Him.
John 5:19-20,28-30 (LGV) 19 Then Jesus responded and said to them, “Truly, truly, I tell you, the Son is powerless to perform from himself – not even one thing – except as He may observe the Father performing. For whatever He should be performing, these things also the Son likewise does. 20 For the Father loves the Son and is showing Him everything which He is doing. And greater deeds than these things He will be showing Him so that you may marvel. … 28 Do not marvel at this, that He is a son of man, because an hour is coming in which all those in the graves shall hear His voice 29 and they will come out, those having done good into resurrection of life, but those practicing what is detestable into resurrection of condemnation. 30 I am powerless to perform from Myself – not one thing. According as I hear I judge, and My judgment is just because I do not seek My will, but the will of [My] Father, the one having sent Me.
The point of this entire section is to show that Jesus did not (at that time) possess a divine ontological nature. As Man, He was no longer of the God “kind.” Notice His statement in verse 28, “Do not marvel at this, that He is a son of man,” a human. God was indeed His literal “Father,” and He was literally the “Son of God” because of His real origin. But the “Son of God” became the “Son of Man,” which explains this disparity. Note that Jesus did not deny what they had inferred by His claim that God was His own personal “Father.” Nor did he challenge their assumption that such would necessarily imply that He was of the God “kind” which itself would imply that the healings were by His own power. Instead, He flatly denied that He was the source of the obvious divine power which performed the healings.
This was actually a brilliant strategy from Jesus, because by claiming that the Father was actually doing the miracles, they had nothing to charge Him with for allegedly breaking the Sabbath. On the other hand, by His clear denials that the power to heal was His own, they could not charge Him with blasphemy either because such a denial necessarily meant He was not claiming divinity, as calling God one’s own Father required in their minds.
John 5 is an excellent chapter to prove that Trinitarianism’s “hypostatic union” doctrine is false (fully God and fully Man), since Jesus had no power to heal or perform miracles from Himself. God did all of the works through Him, as understood by Nicodemus according to John 3:2, as stated plainly by Jesus in John 14:10-11, and as stated plainly by Peter in Acts 2:22 and Acts 10:38. Yet this passage is just as problematic for Unitarians because of the implications of calling God His own Father, which does indeed indicate equality with God in ontological nature at the time of His begetting out of God. Jesus’ statement that God was His own Father was absolutely true because it pointed to His origin out of God at the beginning. His origin cannot be changed. However, His ontological nature could and was changed.
In closing this post, I would like to suggest a theory for why in the second chapter John recorded Jesus’ first miracle which was not mentioned in the synoptic Gospels. In that impossible miracle there was a complete transformation in ontological nature in “the water which had become wine.” The word “had become” is the same verb used in John 1:14, “and Logos became flesh,” and in Phil. 2:7, the one who emptied Himself of the form of God then “became in the likeness of men.” This term in these passages describes a total transformation of ontological nature from one “kind” to another. What better illustration could there be? Water is odorless and colorless, representing the divine Logos as “Spirit.” Jesus referred to God’s Spirit as “living water” in John 7:38-39. Wine is a representation of blood, since ancient times called the “blood of the grape.” Jacob prophesied of Christ with these words: “The scepter shall not depart from Judah, Nor a lawgiver from between his feet, Until Shiloh comes; And to Him shall be the obedience of the people. Binding his donkey to the vine, And his donkey’s colt to the choice vine, He washed his garments in wine, And his clothes in the blood of grapes” (Gen. 49:10-11 NKJ). Jesus referred to the third cup of wine at the Passover, “this is my blood.” The old wine at the wedding feast where Jesus performed this miracle is a perfect metaphor for the blood of bulls and goats which could never take away sin. It was quickly discovered that the water which had become wine through an ontological transformation was far superior to the old wine. Also, the new wine could not be put into old wineskins (the old priesthood) but was charged to new wineskins (the Apostles). Every detail of this actual miracle forms a perfect allegory of the main message of the New Testament. By this “sign” John claimed that Jesus “manifested His glory.”
 It was lawful to do good works on the Sabbath, including healing the sick (Matt. 12:9-14; Luke 13:11-17; John 7:19-24).
 This is the same word used twice in John 1:11.
 Cf. John 8:42 (LGV)
 1 Kings 8:27 ESV
 Exod. 3:2-6
 Exod. 23:20-23
 John 2:9
 Heb. 10:11