Exodus 15:23 And when they came to Marah, they could not drink of the waters of Marah, for they were bitter; therefore the name of it was called Marah.
Sometimes you go places where you can't get what you need, even the most basic things that humans need for survival. Sometimes, figuratively, all you need is a drink of cool, clear, fresh water. But all you see is bitter tasting liquid that people try to pass off as water. You taste it, and you know it is not fit to drink. So what do you do? Do you drink it or do you move on. Or do you pray for a miracle, something to make the bitter waters sweet so that you don't faint from thirst.