John 5:18 Therefore the Jews sought the more to kill him, because he not only had broken the sabbath, but said also that God was his Father, making himself equal with God.
John 5:19 Then answered Jesus and said unto them, Verily, verily, I say unto you, The Son can do nothing of himself, but what he seeth the Father do: for what things soever he doeth, these also doeth the Son likewise.
When one reads the first part of John 5:19 one may walk away with the idea that apart from God, Jesus is powerless. After all, Jesus states: “I can do nothing of my self, except those things that I see God the Father do.” However, upon reading the entire verse, we realize that the exact opposite is true. Meaning, if Jesus does whatever God does (as the second half of John 5:19 asserts), then it follows that Jesus can do whatever God can do. Moreover, if Jesus can do whatever God can do, then Jesus must be equal to the Almighty God. Interestingly, later on in verse 21, we see a necessary consequence of verse 19: Since God can raise to life whomever He wants to, likewise, Jesus can raise to life whomever he wants as well. As stated earlier, in the John 5:17-24 excerpt Jesus’ intent is to demonstrate that He is not guilty of breaking the Sabbath. We have just seen that in verse 19 Jesus links His acts to God’s acts and by doing so, He has the Jews in the uncomfortable position of accusing God the Father of also breaking the Sabbath. As David Guzik puts it:
He [Jesus] is also saying “If I have broken the Sabbath, so has God also; for I can do nothing but what I see him doing. He is ever governing and preserving; I am ever employed in saving.”
Finally, when Jesus says that He only does what He sees God the Father doing, it is natural to envision two people side by side with the one person imitating the other; but this is not the right way to interpret the verse. Rather, what Jesus is saying is that His will and His actions are not independent from His Father’s will and actions; they are independent Persons with dependent wills and actions (see John 14:10). As such is the case, neither does (or can do) anything independent of the Other. Verse 19 then becomes a proof-text for the Christian doctrine of the Trinity. Regarding verse 19, Dr. John P. Lange in his Commentary on the OT and NT, notes that this verse “excludes the idea of imitation and the analogy of master and servant, or teacher and pupil; it points to the equality of the Son with the Father. The Son does the same things with the same power and in the same manner.”
So, we see that if a person is able to do all things that God can do, by definition, that person must be God. Jesus says He does everything that God does, so Jesus is saying that He is God.