15 Perhaps we can more appropriately say this, that in the saying, “God rested on the seventh day,” he signified by a great mystery the Lord and our Saviour Jesus Christ Himself, who spoke and said, “My Father works hitherto, and I work.” For the Lord Jesus is, of course, God. For He is the Word of God, and you have heard that “in the begin ning was the Word;” and not any word whatsoever, but “the Word was God, and all things were made by Him.” He was perhaps signified as about to rest on the seventh day from all His works.
For, read the Gospel, and see what great works Jesus wrought. He wrought our salvation on the cross, that all things foretold by the prophets might be fulfilled in Him. He was crowned with thorns; He hung on the tree; said, “I thirst,” received vinegar on a sponge, that it might be fulfilled which was said, “And in my thirst they gave me vinegar to drink.” And when all His works were completed, on the sixth day of the week, He bowed His head and gave up the ghost, and on the Sabbath day He rested in the tomb from all His works.
Therefore it is as if He said to the Jews, “Why do you expect that I should not work on the Sabbath? The Sabbath day was ordained for you for a sign of me. You observe the works of God: I was there when they were made, by me were they all made; I know them. 'My Father works hitherto.' The Father made the light, but He spoke that there should be light; if He spoke, it was by His Word He made it: His Word I was, I am; by me was the world made in those works, by me the world is ruled in these works.
My Father worked when He made the world, and hitherto now works while He rules the world: therefore by me He made when He made, and by me He rules while He rules.” This He said, but to whom? To men deaf, blind, lame, impotent, not acknowledging the physician, and as if in a frenzy they had lost their wits, wishing to slay Him.
Source: Tractates on the Gospel of John (New Advent)