Moses asked the LORD for help, and the LORD told him to throw a piece of wood into the water. Moses did so, and the water became fit to drink. At Marah the LORD tested his people and also gave them some laws and teachings.
Don't forget how the LORD your God has led you through the desert for the past forty years. He wanted to find out if you were truly willing to obey him and depend on him,
and I'm going to let those enemies stay. I'll use them to test Israel, because then I can find out if Israel will worship and obey me as their ancestors did.
And the LORD had another reason for letting these enemies stay. The Israelites needed to learn how to fight in war, just as their ancestors had done. Each new generation would have to learn by fighting