After the Children of Israel crossed the Red Sea they sang “the Song of the Sea” (“Shirat Ha-yam” {שירת הים} in Hebrew).
References to this unique biblical poetry can be found, among others, in Psalms, in chapter 114:
“When Israel went out from Egypt, the House of Jacob from a people of strange language, Judah became his sanctuary, Israel his dominion. The sea looked and fled; Jordan turned back…(Psalms 114:1-4)
An old Jewish “Aggadah” {אגדה} which is a tale based on biblical events (but with emphasis on folklore, historical and non-historical) anecdotes and moral exhortations tells us that ‘the Sea looked’ and what caused it to flee (run away or give in).
When the Children of Israel arrived to the shore of the Sea and Moses raised his hand to command the sea, the sea did not want to obey Moses because according to the order of the creation man was created AFTER the sea.
The sea was created on the third day and man was created on the sixth day – hence the sea has priority over man and would not listen and obey a man’s command. But then the sea looked at what Moses brought with him – the bones of Joseph (Exodus 13:19).
Joseph, as we all know, was the youngest son but due to his virtues he ruled over his older brothers and so the sea learned its lesson and ‘fled’ (gave in) as Moses commanded it to do.