13 The Jews persecuted the Lord Jesus because He did these things on the Sabbath day. Let us hear what answer the Lord now made to the Jews. I have told you how He is wont to answer concerning the healing of men on the Sabbath day, that they used not on the Sabbath day to slight their cattle, either in delivering or in feeding them. What does He answer concerning the carrying of the bed? A manifest corporal work was done before the eyes of the Jews; not a healing of the body, but a bodily work, which appeared not so necessary as the healing. Let the Lord, then, openly declare that the sacrament of the Sabbath, even the sign of keeping one day, was given to the Jews for a time, but that the fulfillment of the sacrament had come in Himself. “My Father,” says He, “works hitherto, and I work.” He sent a great commotion among them: the water is troubled by the coming of the Lord, but yet He that troubles is not seen. Yet one great sick one is to be healed by the troubled water, the whole world by the death of the Lord.
Source: Tractates on the Gospel of John (New Advent)