John 5:16 indicates that the Jewish religious leaders rejected all the evidence that was accumulating in regard to Jesus being the Messiah. They persecuted Him and "sought to kill Him." Had Jesus actually violated the Sabbath--and not just their man-made traditions--in healing the man with the infirmity, their seeking to kill Him would not have been wrong (cf. Num. 15:32-36).
Jesus began to defend His actions in John 5:17. It should be understood that one might be able to justify an act in several different ways and may simply choose to be content justifying himself in only one way. Such is the case here. Elsewhere (e.g., Matt. 12:9ff), it can be seen that Jesus was careful to show that His actions on the Sabbath were strictly legal. But, in this case, in order to bring His divine claims plainly before the rulers, He ignored the question as to the human legality of His act that He might present, without confusion, its divine legality. Thus, He only uses one method of justification in the following verses: as the Son of God, Jesus was imitating His heavenly Father and, consequently, was doing nothing wrong.
Jesus claimed a unique relationship as God's Son in John 5:17. He also stated that His Father had been "working until now". Though God rested on the seventh day of the creation week (Gen. 2:2), He had not ceased to be active since then--even on the Sabbath. The work mentioned here by Jesus is not physical labor but God's giving of providence and mercy. Even on the Sabbath, He continued to send the rain and other blessings. Even on the Sabbath, He continued to reign over the world and uphold all things by the power of His word (cf. Heb. 1:1-3). Jesus does work on the Sabbath in the sense that He does good on that day (cf. Matt. 12:12), just like His Father!
The religious leaders rightly interpreted Jesus as claiming to be God's Son and also as an equal to God (John 5:18). They understood that He believed Himself to be divine. This made them all the more furious! In their view, He was not only guilty of breaking the Sabbath, but now He was a blasphemer too! Jesus' response in 5:19 is essentially this: the Son only does what He sees the Father do. Therefore, everything that the Son does is in perfect harmony with the Father.
In 5:20, Jesus declared that "the Father loves the Son." The Greek word for "love" used here denotes a warm, tender affection indicating the special relationship that existed between Them. Because of this love, nothing the Father did was withheld from the Son. The Son had perfect knowledge of the Father. The Father would show the Son greater things than the world had already seen Him do. In the verses to follow, Jesus described those "greater works" of raising the dead, judging the world, and giving eternal life. Such marvelous deeds would be done to cause wonder and astonishment.
Since the verbs in 5:21 are in the present tense, and since Jesus was not known to have raised the physically dead before this point in His ministry, it is assumed that He spoke of Himself as raising the spiritually dead. "The Son gives life to whom He will", and He wills to give it to all who obey God (Matt. 7:21-23; Heb. 5:8,9). God will not save certain ones in an arbitrary fashion, as Calvinists claim. Provisions for the salvation of all have been made. The fact that not all will be saved is not due to any random selection on the part of the Son but because of the unwillingness of most to accept the plan offered to them (cf. II Pet. 3:9).
John 5:22, as well as many other passages, communicates the truth that the Father has given the Son the responsibility of judging all men (cf. Matt. 25:31,32; Acts 10:42; etc.). This responsibility was given to the Son that He might receive honor as the Father does (John 5:23). The failure of man to give proper honor to the Son actually dishonors the Father who sent the Son. A perfect example of this type of dishonor is found in the religious leaders who were trying to take Jesus' life.