I had the morning free today, so I made my way to one of my favorite secret getaways: the library at St. Joseph's Seminary. There I read some of St. Bonaventure's commentary on the gospel of St. John. I made it up to chapter two, and Bonaventure's interpretation of the wedding at Cana, which I found sweet.
The wedding at Cana can be seen as an allegory for the marriage of the soul with God. The stone jars represent the state of our souls. At first they are empty, illustrating our state of undevotion and dryness. They must first be filled with water, and this water is the tears of our prayer. Then, at the intercession of Mary, Jesus transforms the water of our tears into the joy and warmth of the wine, which is the spiritual unction of the presence of God in our prayer.
I wasn't following the notes too closely at this point--I was running out of time--so I'm not sure if this interpretation has history.