Reading quote (below) from Preaching the Gospels Without Blaming the Jews: A Lectionary Commentary (2004) by Ronald J. Allen & Clark M. Williamson; p. 184.
The term “deep water” translates the Greek bathos, that is translated “deep” in Gen. 1:2. The deep was a fierce, untamed, dark, primal sea that existed before God began to speak into existence and bring into covenantal relationship the elements of creation. In Jewish mythology, the sea often represents chaos.