The story of Jesus and his mother, Mary, at the wedding celebration in Cana (and the crisis of running out of wine) reminds us of life's paradox that happiness and sorrow exist together. Indeed, our 'cup of life' is a melange of joy and pain which we are invited to drink to the last drops. It is this deeper truth which John points to as he emphasizes that the 'glory of Jesus' is manifested as the water of creation is transformed into the new wine of Christ's sacrificial love.
