In a literal sense, Mayim Rabim (Vast Waters) is a depiction of the enormous power and majesty of the ocean's waves. However there is a deeper meaning to water.
There is a concept in Judaism that Torah is like water. In my life I am constantly interacting with sacred texts through learning both its written words and understanding it deeper through the oral tradition. The metaphorical reference to water is that just as we cannot live without water, so too will we whither away without Torah learning. It defines what it means to be a Jew. Understanding the nuances of morality and refining ones spirituality, at the same time bringing holiness to all aspects of our lives.