Exodus 15

This chapter describes the song of Miriam and of Moses.  The text is written in a stylistically different graphic pattern, one that may suggest the bricks of slavery or the stepping stones for passing through the Red Sea (http://www.beth-elsa.org/dll020604.htm).

The song of Miriam (the name is derived from the word for bitter) may have been a complete song in itself, sung in counterpoint. http://www.upj.org.au/Parashatbeshalach2003.htm  What is clear is that it was sung accompanied by tambourines and dancing.

The section continues with the Israelites thirsting after three days in the desert without water and only a bitter spring, Marah, to quench that thirst.  One might wonder whether the bitterness of the spring is related to Miriam.  Commentary connects the bitterness of Marah to the mountain on which the Torah was delivered, Moriah (http://www.ohrtorahstone.org.il/parsha/5763/beshalach63.htm) 

In any event, the bitterness is sweetened by a piece of wood. Then there is an odd discontinuity, as God "tests" the Israelites-- how, exactly, we are not told here-- and promises to spare them the diseases of the Egyptians if they will obey His decrees.  He asserts Himself as the One who heals  Apparently, he also provides law to them here, but what law is not specified. Perhaps it was the Sabbath law (http://www.geocities.com/m_yericho/ravkook/BSHALA64.htm).  If so, it could connect to Jesus' healing on the Sabbath. 

Finally, after this long drought, the Israelites arrive at Elim, meaning strength, where there is a spring for each tribe of Israel and a palm tree, symbolically, for every nation on earth (http://www.ohrtorahstone.org.il/parsha/5763/beshalach63.htm)