On the third day there was a wedding in Cana of Galilee, and the mother of Jesus was there. 2Jesus and his disciples had also been invited to the wedding. 3When the wine gave out, the mother of Jesus said to him, “They have no wine.” 4And Jesus said to her, “Woman, what concern is that to you and to me? My hour has not yet come.” 5His mother said to the servants, “Do whatever he tells you.” 6Now standing there were six stone water jars for the Jewish rites of purification, each holding twenty or thirty gallons. 7Jesus said to them, “Fill the jars with water.” And they filled them up to the brim. 8He said to them, “Now draw some out, and take it to the chief steward.” So they took it.9When the steward tasted the water that had become wine, and did not know where it came from (though the servants who had drawn the water knew), the steward called the bridegroom 10and said to him, “Everyone serves the good wine first, and then the inferior wine after the guests have become drunk. But you have kept the good wine until now.” 11Jesus did this, the first of his signs, in Cana of Galilee, and revealed his glory; and his disciples believed in him. (NRSV)The narrative has now moved on from the calling of the disciples to the start of Jesus' public ministry. The narrative itself ties with other important themes throughout the gospel and thus does introduce the nature of Jesus' ministry (see Moloney's commentary for a concise treatment of themes with references). Thus, as Michaels has pointed out, this is more of a pronouncement story than a miracle story. Or perhaps, better, a miracle story that functions as a pronouncement. Jesus goes to a wedding with some of his disciples and the wine runs out. Mary, his mother points this out to him, presumably hoping for him to intervene in some way. Jesus responds in a way that distances himself from his mother. Mary is undeterred and tells the servants to do whatever Jesus tells them to do. Verses 4-5 are quite difficult in my opinion. It's hard to see verse four as anything but a rejection of Mary. McHugh's translation captures it nicely, 'What relationship is there, woman, between you and me, now that my hour is approaching?'
What is Jesus' hour? It must be the demonstration of Jesus' glory, culminating in his death. The miracle performed here is a precursor for what will be demonstrated more widely later on in the gospel. Jesus' rebuff of his mother then must be understood as expressing his freedom from human influence (so Bultmann, among others). Even familial relations cannot be counted on. Jesus was truly his own man.
Why then did Mary persist? She is presented here as a model disciple. She has faith even prior to the demonstration of Jesus miracle. However, we do, as well, need to reckon with the possibility that Jesus's response is from the hand of the editor, because its still very hard to hold Jesus response and Mary's instructions to the servants together.
There were six large jars for purification that Jesus instructed to be filled with water. I think it's impossible to adjudicate whether or not we are supposed to understand this narrative element as indicating that what Jesus provides supersedes the Mosaic covenant. I think we are on much surer ground in seeing this miracle as expressing that Jesus' ministry is the flowering of the Messianic age, an age (as McHugh points out) overflowing with the wine of wisdom. Jesus, as Wisdom incarnate is coming to give wisdom by the Spirit to all who will receive and recognize it.
The story ends ironically. Jesus performs a great miracle but it isn't recognized. The wrong bridegroom is called. Jesus the true bridegroom displayed his glory, but it was only ascertained by his followers, who responded with faith. Thus the story is both ironic and indicative of what is to come.