מלכים ב, פרק ב׳, פסוק כ״א

Elisha the Prophet performs a miraculous act, transforming a source of death and loss into a wellspring of life. He goes directly to the exact spring from which the waters flow, targeting the very origin of the problem. By throwing salt into the spring, he initiates an event that completely defies the laws of nature, highlighting direct Divine intervention.

Naturally, salt ruins water and makes it undrinkable. Therefore, using a harmful substance to actually cure the water is a miracle within a miracle, a deliberate double wonder designed to magnify the greatness of the event [רש״י, מצודת דוד, ביאור שטיינזלץ]. The healing itself is an act of God sweetening the water [ביאור שטיינזלץ].

With this act comes a promise that the water will never again cause harm. Because the spoiled water was the root cause of the previous tragedy, healing it ensures the land will no longer bring about death and bereavement [רד״ק, מצודת דוד]. The repeated emphasis on death and loss simply reinforces this exact same idea using different terms [מצודת ציון].