Moses' first miracle was a plague - turning water into blood (Ex. 7:19), which speaks of judgement. Jesus' miracle speaks of grace, turning water into wine. He brings fullness where there was emptiness, joy where there was disappointment, and something internal for that which was only external. This miracle is a sign that points to The Gospel - the availability of the Kingdom of God - and it is an extravagant gift. Jesus is extravagant.