From: John 5:17-30
The Cure of a Sick Man at the Pool at Bethzatha (Continuation)
 But Jesus answered them, "My Father is working still, and I am working."  This was why the Jews sought all the more to kill Him, because He not only broke the Sabbath but also called God His Father, making Himself equal with God.
Christ Defends His Action
 Jesus said to them, "Truly, truly, I say to you, the Son can do nothing of His own accord, but only what He sees the Father doing; for whatever He does, that the Son does likewise.  For the Father loves the Son, and shows Him all that He Himself is doing; and greater works than these will He show Him, that you may marvel.  For as the Father raises the dead and gives them life, so also the Son gives life to whom He will.  The Father judges no one, but has given all judgment to the Son,  that all may honor the Son, even as they honor the Father. He who does not honor the Son does not honor the Father who sent Him.  Truly, truly, I say to you, he who hears My word and believes Him who sent Me, has eternal life; he does not come into judgment, but has passed from death to life.
 "Truly, truly, I say to you, the hour is coming, and now is, when the dead will hear the voice of the Son of God, and those who hear will live.  For as the Father has life in Himself, so He has granted the Son also to have life in Himself,  and has given Him authority to execute judgment, because He is the Son of Man.  Do not marvel at this; for the hour is coming when all who are in the tombs will hear His voice  and come forth, those who have done good, to the resurrection of life, and those who have done evil, to the resurrection of judgment.
 "I can do nothing on My own authority; as I hear, I judge; and My judgment is just, because I seek not My own will but the will of Him who sent Me."
17-18. "My Father is working still, and I am working": we have already said that God is continually acting. Since the Son acts together with the Father, who with the Holy Spirit are the one and only God, our Lord Jesus Christ, the Son of God, can say that He is always working. These words of Jesus contain an implicit reference to His divinity: the Jews realize this and they want to kill Him because they consider it blasphemous. "We all call God our Father, who is in Heaven (Isaiah 63:16; 64:8). Therefore, they were angry, not at this, that He said God was His Father, but that He said it in quite another way than men. Notice: the Jews understand what Arians do not understand. Arians affirm the Son to be not equal to the Father, and that was why this heresy was driven from the Church. Here, even the blind, even the slayers of Christ, understand the works of Christ" (St. Augustine, "In Ioann. Evang., 17, 16). We call God our Father because through grace we are His adopted children; Jesus calls Him His Father because He is His Son by nature. This is why He says after the Resurrection: "I am ascending to My Father and your Father" (John 20:17), making a clear distinction between the two ways of being a son of God.
19. Jesus speaks of the equality and also the distinction between Father and Son. The two are equal: all the Son's power is the Father's, all the Son does the Father does; but they are two distinct persons: which is why the Son does what He has seen the Father do.
These words of our Lord should not be taken to mean that the Son sees what the Father does and then does it Himself, like a disciple imitating his master; He says what He says to show that the Father's powers are communicated to the Son through generation. The word "see" is used because men come to know things through the senses, particularly through the sight; to say that the Son sees what the Father does is a way of referring to all the powers which He receives from Him for all eternity (cf. St. Thomas Aquinas, "Comm. on St. John, in loc.").
20-21. When He says that the Father shows the Son "all that He Himself is doing", this means that Christ can do the same as the Father. Thus, when Jesus does things which are proper to God, He is testifying to His divinity through them (cf. John 5:36).
"Greater works": this may be a reference to the miracles Jesus will work during His lifetime and to His authority to execute judgment. But THE miracle of Jesus was His own resurrection, the cause and pledge of our own (cf. 1 Corinthians 15:20ff), and our passport to supernatural life. Christ, like His Father, has unlimited power to communicate life. This teaching is developed in verses 22-29.
22-30. Authority to judge has also been given by the Father to the Incarnate Word. Whoever does not believe in Christ and in His word will be condemned (cf. 3:18). We must accept Jesus Christ's lordship; by doing so we honor the Father; if we do not know the Son we do not know the Father who sent Him (verse 23). Through accepting Christ, through accepting His word, we gain eternal life and are freed from condemnation. He, who has taken on human nature which He will retain forever, has been established as our judge, and His judgment is just, because He seeks to fulfill the Will of the Father who sent Him, and He does nothing on His own account: in other words, His human will is perfectly at one with His divine will; which is why Jesus can say that He does not do His own will but the Will of Him who sent Him.
22. God, being the Creator of the world, is the supreme Judge of all creation. He alone can know with absolute certainty whether the people and things He has created achieve the end He has envisaged for them. Jesus Christ, the Incarnate Word, has received divine authority (cf. Matthew 11:27; 28:18; Daniel 7:14), including the authority to judge mankind. Now, it is God's will that everyone should be saved: Christ did not come to condemn the world but to save it (cf. John 12:47). Only someone who refuses to accept the divine mission of the Son puts himself outside the pale of salvation. As the Church's Magisterium teaches: "He claimed judicial power as received from His Father, when the Jews accused Him of breaking the Sabbath by the miraculous cure of a sick man. [...] In this power is included the right of rewarding and punishing all men, even in this life" (Pius XI, "Quas Primas, Dz-Sch 3677"). Jesus Christ, therefore, is the Judge of the living and the dead, and will reward everyone according to his works (cf. 1 Peter 1:17).
"We have, I admit, a rigorous account to give of our sins; but who will be our judge? The Father [...] has given all judgment to the Son. Let us be comforted: the eternal Father has placed our cause in the hands of our Redeemer Himself. St. Paul encourages us, saying, Who is [the judge] who is to condemn us? It is Jesus Christ, who died [...] who indeed intercedes for us (Romans 8:34). It is the Savior Himself, who, in order that He should not condemn us to eternal death, has condemned Himself to death for our sake, and who, not content with this, still continues to intercede for us in Heaven with God His Father" (St. Alphonsus Liguori, "The Love of Our Lord Jesus Christ Reduced To Practice", Chapter 3).
24. There is also a close connection between hearing the word of Christ and believing in Him who sent Him, that is, in the Father. Whatever Jesus Christ says is divine revelation; therefore, accepting Jesus' words is equivalent to believing in God the Father: "He who believes in Me, believes not in Me, but in Him who sent Me.... For I have not spoken on My own authority; the Father who sent Me has Himself given Me the commandment what to say and what to speak" (John 12:44, 49).
A person with faith is on the way to eternal life, because even in this earthly life he is sharing in divine life, which is eternal; but he has not yet attained eternal life in a definitive way (for he can lose it), nor in a full way: "Beloved, we are God's children now; it does not yet appear what we shall be, but we know that when He appears we shall be like Him" (1 John 3:2). If a person stays firm in the faith and lives up to its demands, God's judgment will not condemn him but save him.
Therefore, it makes sense to strive, with the help of grace, to live a life consistent with the faith: "If men go to so much trouble and effort to live here a little longer, ought they not strive so much harder to live eternally?" (St. Augustine, "De Verb. Dom. Serm.", 64).
25-30. These verse bring the first part of our Lord's discourse to a close (it runs from 5:19 to 5:47); its core is a revelation about His relationship with His Father. To understand the statement our Lord makes here we need to remember that, because He is a single (divine) person, a single subject of operations, a single I, He is expressing in human words not only His sentiments as a man but also the deepest dimension of His being: He is the Son of God, both in His generation in eternity by the Father, and in His generation in time through taking up human nature. Hence Jesus Christ has a profound awareness (so profound that we cannot even imagine it) of His Sonship, which leads Him to treat His Father with a very special intimacy, with love and also with respect; He is aware also of His equality with the Father; therefore when He speaks about the Father having given Him life (verse 26) or authority (verse 27), it is not that He has received part of the Father's life or authority: He has received absolutely all of it, without the Father losing any.
"Do you perceive how their equality is shown and that they differ in one respect only, namely, that one is the Father, while the other is the Son? The _expression `He has given' implies this distinction only, and shows that all other attributes are equal and without difference. From this it is clear that He does everything with as much authority and power as the Father and is not endowed with power from some outside source, for He has life as the Father has" (St. John Chrysostom, "Hom. on St. John", 39, 3).
One of the amazing things about these passages of the Gospel is how Jesus manages to express the sentiments of God-Man despite the limitations of human language: Christ, true God, true man, is a mystery which the Christian should contemplate even though he cannot understand it: he feels bathed in a light so strong that it is beyond understanding, yet fills his soul with faith and with a desire to worship his Lord.
Source: "The Navarre Bible: Text and Commentaries". Biblical text taken from the Revised Standard Version and New Vulgate. Commentaries made by members of the Faculty of Theology of the University of Navarre, Spain. Published by Four Courts Press, Kill Lane, Blackrock, Co. Dublin, Ireland. Reprinted with permission from Four Courts Press and Scepter Publishers, the U.S. publisher.