Beshalach - R'vi'i
What the Servant Girl Saw
G-d told Moshe to again reach out over the sea, this time to cause it to close up on the army of Egypt. This he did, and the soldiers were covered by the sea.
When the Jews saw their former pursuers wash up on the shore, they were in awe of G-d. They placed their faith in Him and in Moshe, whom He had delegated as His messenger. Then, the Jews sang a song of praise to G-d, which we recite daily as part of the morning service. We call this song the Shira, "The Song." This is the song of praise par excellence. It's not surprising that they sang such a superlative song, since the Midrash tells us that a simple servant girl experienced more at the Red Sea than the prophet Yechezkel (Ezekiel) experienced in his visions of G-d's "chariot."
In the Shira, the Jews praise G-d's might and power in executing judgment on their oppressors. The Egyptians thought to overtake the Jews, but G-d scuttled both their plans and them. He is unique in His ability to work wonders and other nations are in awe of what He has done. (Bullet points can't come close to doing justice to the Shira. Really, read it in the original, with a good translation and commentary.) Miriam and the women sang and danced separately from the men. (This is a Biblical precedent for the practice of separate dancing.)
But trouble started soon enough. After three days of travel, they hadn't come to a source of water. They set up camp and discovered that the water in that place was bitter and undrinkable. (This caused them to call the place Marah, meaning bitter.) The people complained to Moshe, who turned to G-d. G-d had him throw a certain type of wood into the water, which caused it to become sweet and potable. It was at Marah that G-d taught the Jews some mitzvos through which they would be able live; to ignore them would be to invite plagues similar to those suffered by the Egyptians.