2 Kings 2:19-22

One day the people of Jericho said, “Elisha, you can see that our city is in a good spot. But the water from our spring is so bad that it even keeps our crops from growing.” He replied, “Put some salt in a new bowl and bring it to me.” They brought him the bowl of salt, and he carried it to the spring. He threw the salt into the water and said, “The LORD has made this water pure again. From now on you'll be able to grow crops, and no one will starve.” The water has been fine ever since, just as Elisha said.