Praised be Jesus and Mary, now and forever.
The first reading speaks about the Messiah, and indeed, in it, God speaks to the Messiah. The Christ will restore the land, saying to the prisoners, "Come out." To those in darkness, "Show yourselves." This is exactly what Jesus will say to Lazarus, "Come out." Lazarus will then come out of the darkness of the tomb and show himself. He will be able to do this because Christ will raise him from the dead, even though he will have been in the tomb for four days by then. He will raise that man from bodily death and decay to show His power to raise men from spiritual death and degradation.
But the good things Christ comes to bring will not meet with a good reception from everyone. Those who, out of envy, do not accept Him find an excuse in the Sabbath. They say that if Jesus heals on the Sabbath, he sins and therefore he cannot be from God. Jesus responds, "My Father is at work until now. So I am at work." What does He mean? The law of Moses teaches men to follow God's example in resting on the Sabbath. Jesus is indeed following this example because He is only working in the way His Father is still working. God's rest on the Sabbath after finishing creation does not mean He no longer confers benefits. He continues to preserve and restore what He created.
As God grants man the energy to heal his body and recover from illness, so Christ granted healing to the man who had been ill for 38 years. Furthermore, the purpose of the Sabbath rest is to give man relief from labor and leisure to worship God. Christ relieved the man who was ill with a miracle that is reason to give praise to God. 
But Jesus's response provides another pretext for rejecting Him, because He presents Himself as equal to God the Father. And thus we draw closer to the passion and death of our Lord. This is why we read Gospels like this in these last weeks of Lent. How does Christ respond to their outrage? He gives two proofs that He is equal to the Father. The first is that He raises the dead. He demonstrates this with the daughter of Jairus, the son of the widow of Nain, and Lazarus. The second is that He has power to exercise judgment, which is a divine prerogative. These two are connected because Christ will use His power to raise the dead primarily to call them to judgment that will happen at the end of the world. That is the hour of which He speaks in which all who are in the tombs will hear His voice and will come out. Once again, we have those words from the first reading, "Come out." Those who have done good deeds will come forth to the resurrection of life, but those who have done wicked deeds to the resurrection of condemnation.
It might seem that Jesus is acting imprudently. He chooses to heal on the Sabbath, provoking the Pharisees, and He speaks of His divinity to people who do not want to believe. Yet we see that He who is Wisdom in person always acts this way, and so there must be a reason. We find a reason in what He says, "Whoever hears my word and believes in the one who sent me has eternal life and will not come to condemnation but has passed from death to life." Faith is indispensable for salvation. Therefore, when He encounters people who do not believe, He increasingly pushes them to believe, making ever bolder statements. He came to save, and He does not want to give up on anyone. His love is like that love of a mother of which God speaks in the first reading, and even indeed, indeed even more than a mother. Some mothers do indeed forget their children, but God will never forget any one of us. He will not give up on trying to save us even to the end of our life, and moreover, Jesus's time is limited. He has only a little more than three years of public ministry, so this is why He is, we might say, so aggressive in trying to bring people to faith.
This is how He expresses what He is doing, "The hour is coming and is now here when the dead will hear the voice of the Son of God and those who hear will live." He is not talking here about those who are physically dead, but those who are spiritually dead, though there is a parallel in that He can give life in both senses. He says the hour is coming because it was prophesied. The hour is now here because He is already fulfilling the prophecies by His ministry. In His preaching, He speaks to those who are dead to God in that they are without God's grace and therefore without eternal life. Those who listen to Him in the sense of accepting what they hear will live because they believe. By faith they are justified and receive eternal life. So, in this sense, those who listen to the Son of God will live.
There is another reason why He speaks even to those who don't listen. What He says, He must say because He came to bring the fullness of revelation. If He does not say it to the crowds, there is no one else after Him who will say it. There is no other incarnate Word. Therefore, He speaks to reveal all the truth, at least for the benefit of those who will believe. Some will believe when Christ speaks. Far more will believe when the Church repeats His teaching in every age until the end of the world. 
Certainly, there is also a reason why He deliberately heals on the Sabbath day. One reason could be that He wants to show the true meaning of the law of Moses, which the scrupulous Pharisees had distorted. But it may also be that He heals on the Sabbath because there will be a Sabbath on which He will heal all mankind. That will be the great Sabbath, the day after His crucifixion, in which God, having completed His work, rests in the tomb, and by that rest prepares His resurrection. The resurrection of the God-man will ultimately raise all the dead, those who have done good deeds to the resurrection of life, and those who have done wicked deeds to the resurrection of condemnation.
Praised be Jesus and Mary, now and forever.