The following is an excerpt from The MacArthur New Testament Commentary on John 2.

Now there were six stone waterpots set there for the Jewish custom of purification, containing twenty or thirty gallons each. Jesus said to them, “Fill the waterpots with water.” So they filled them up to the brim. And He said to them, “Draw some out now and take it to the headwaiter.” So they took it to him. When the headwaiter tasted the water which had become wine, and did not know where it came from (but the servants who had drawn the water knew), the headwaiter called the bridegroom, and said to him, “Every man serves the good wine first, and when the people have drunk freely, then he serves the poorer wine; but you have kept the good wine until now.” (2:6–10)The stone waterpots were, as John explained for the benefit of his Gentile readers, used for the Jewish custom of purification. Ceremonial washings were an integral part of first-century Judaism:   The Pharisees and all the Jews do not eat unless they carefully wash their hands, thus observing the traditions of the elders; and when they come from the market place, they do not eat unless they cleanse themselves; and there are many other things which they have received in order to observe, such as the washing of cups and pitchers and copper pots. (Mark 7:3–4)The Jews used stone waterpots to hold the water used for ritual purification because they believed that, unlike earthenware pots (Lev. 11:33), they did not become unclean. Unlike the smaller one used by the Samaritan woman to draw water from a well (4:28), these were large pots, containing twenty or thirty gallons each. Such a large amount of water was needed not only to accommodate the guests, but also because the cooking and eating utensils had to be washed (Mark 7:4).

Mary’s faith and confidence in her Son were not misplaced. As she had foreseen, He responded by commanding the servants, “Fill the waterpots with water.” In response, they filled them up to the brim, either by topping them off, or by emptying and refilling them. This seemingly insignificant detail, that the water was up to the very top, shows that nothing was added to the water, and that what followed was indeed a transformation miracle. By ordering the jars to be completely filled before He transformed the water in them into wine, Jesus also displayed His magnanimous grace (cf. 1:14, 16–17). Such a large amount of wine (120 to 180 gallons) was more than enough to last for the rest of the celebration. Jesus not only rescued the bride and groom from an embarrassing situation, but the leftover wine also provided them with a generous wedding present.

After the pots were filled, Jesus instructed the servants to draw some out and take the instantly created wine to the headwaiter. Jewish sources do not make clear whether this individual was the head servant, or a guest chosen to preside over the banquet. That he summoned the groom and spoke to him as at least his equal (vv. 9–10) suggests the latter. In either case, he served as the master of ceremonies at the feast. Since he was responsible for making sure that the guests were supplied with food and drink, the servants took the wine to him.

To make sure it was acceptable, the headwaiter sampled the food and drink before it was served to the guests. Therefore after the servants brought it to him, he tasted the water which had become wine. Though he did not know where it came from (though of course the servants who had drawn the water did), he was astonished at the high quality of this new batch of wine. He called the bridegroom, and said to him, “Every man serves the good wine first, and when the people have drunk freely, then he serves the poorer wine.” There is some historical evidence that most hosts did, as the headwaiter suggested, serve the best wine first (D. A. Carson, The Gospel According to John, The Pillar New Testament Commentary [Grand Rapids: Eerdmans, 1991], 174). In any case, it was only common sense to serve the good wine first and save the poorer wine for later when the people had drunk freely. The verb methusko (drunk freely) literally means “to become drunk,” and is so translated in its only other appearances in the New Testament (Luke 12:45; Eph. 5:18; 1 Thess. 5:7; Rev. 17:2). That does not mean, however, that this particular banquet had become a drunken orgy; the headwaiter was speaking from his own experience. But much to his surprise (and no doubt the groom’s as well), it seemed that the groom had kept the good wine until the last. Surely it was the sweetest, freshest wine ever tasted. This wine did not come from the normal process of fermentation, from grapes, vines, the earth and the sun. The Lord brought it into existence from nothing. Truly this was evidence that He is the Creator (John 1:1–4).