What does 2 Kings 2:21 mean?

He went out to the spring, threw the salt in, and said, 'This is what the Lord says: I have healed this water. It will never cause death or miscarriage again.' 2 Kings 2:21 - Modern Text Bible

(Elisha acts as God's agent, declaring the water healed. The salt is a symbol, but the real power is God's word.)