Summary: Jesus teaches about the union of the Father and the Son in their deity, their works, and their plan.
Jesus healed the impotent man, but it was on a Sabbath so the Jews persecuted Jesus:
17But Jesus answered them, My Father worketh hitherto, and I work.
This is His answer against breaking the Sabbath. The Father’s work started and has not stopped. The works Jesus does are a result of the Father’s work. If a person doesn’t believe Jesus, then he doesn’t believe the Father either.
18Therefore 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.
They didn’t hear anything but “My Father” so they wanted to kill Him for blasphemy:
19Then 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.
This is the first part of His answer against blasphemy. Some people think He means that He’s limited in His abilities, but we can’t forget that He is both God and Man at the same time. He can’t be less God and still be God. He is the eternal and omnipresent Word while He is the man Jesus Christ. The point of His statement here is that He’s so united with the Father that it’s impossible for Him to act outside the Father’s will.
Remember His prayer in the garden? “Not as I will, but as you will” (Mt. 26:39). He teaches His disciples to pray, “Thy will be done on earth as it is in heaven” (Mt. 6:10). The healing of the lame man on the Sabbath (and the subsequent command to take up his bed) were from the Son; but the Son does nothing against the will of the Father! It is the will of the Godhead that this man be healed on this day and that He should stand up and carry a load.
20For the Father loveth the Son, and sheweth him all things that himself doeth:
This is the second part of His answer: the Father and the Son are intimately united. The Father and Son are more than allies; they are family.
Think about what the Father said at the Mount of Transfiguration: And there was a cloud that overshadowed them: and a voice came out of the cloud, saying, This is my beloved Son: hear him (Mk. 9:7).
Think also about Matthew 21:33-40: There was a certain householder, which planted a vineyard, and hedged it round about, and digged a winepress in it, and built a tower, and let it out to husbandmen, and went into a far country: 34And when the time of the fruit drew near, he sent his servants to the husbandmen, that they might receive the fruits of it. 35And the husbandmen took his servants, and beat one, and killed another, and stoned another. 36Again, he sent other servants more than the first: and they did unto them likewise. 37But last of all he sent unto them his son, saying, They will reverence my son. 38But when the husbandmen saw the son, they said among themselves, This is the heir; come, let us kill him, and let us seize on his inheritance. 39And they caught him, and cast him out of the vineyard, and slew him. 40When the lord therefore of the vineyard cometh, what will he do unto those husbandmen?