The man departed and told the Jews that it was Jesus who had made him well. For this reason the Jews persecuted Jesus, and sought to kill Him, because He had done these things on the Sabbath.
But Jesus answered them, "My Father has been working until now, and I have been working." Therefore the Jews sought all the more to kill Him, because He not only broke the Sabbath, but also said that God was His Father, making Himself equal with God.
John 5:15-18 (NKJV)