14 Next he brings us back to Jerusalem, and tells the story of the healing of the man who had an infirmity of thirty-eight years' standing. What words are spoken on this occasion, and how ample is the discourse! Here we are met by the sentence, “The Jews sought to kill Him, because He not only broke the Sabbath, but said also that God was His Father, making Himself equal with God.” In this passage it is made sufficiently plain that He did not speak of God as His Father in the ordinary sense in which holy men are in the habit of using the phrase, but that He meant that He is His equal.
For, a little before this, He had said to those who were impeaching Him with violating the Sabbath day, “My Father works hitherto, and I work.” Then their fury flamed forth, not merely because He said that God was His Father, but because He wished it to be understood that He was equal with God, when He used the phrase, “My Father works hitherto, and I work.” In which utterance He also shows it to be matter of course that, as the Father works, the Son should work also; because the Father does not work without the Son. And this is in accordance with what He states a little further on in the same passage, when these parties were incensed at His declaration, namely, “For what things soever He does, these also does the Son likewise.”
Source: The Harmony of the Gospels (New Advent)