It is possible to add (and [this additional concept is important] for {the matter to be explained} is a matter of necessity for the [entire] generation [as a whole], and for many individuals [in a personal sense]): The meaning of the phrase “I will heal him” is that the healing will be accomplished by G‑d.1

In general, healing (even healing which comes about through an intermediary, a human being) emanates [from G‑d], “G‑d says.” In this instance, since the healing is drawn down [directly] from G‑d Himself, “I G‑d am your healer,”2 it causes that [as the above verse continues,] “all illnesses... I will not place upon you,” ([i.e., not merely that G‑d will heal illness, but that He will prevent illness from occurring] from the very outset).3

Moreover, even when the healing accomplished by “I G‑d am your healer” comes, for various reasons, after an undesirable event took place, this healing can be completed without leaving a trace of infirmity, causing it to appear as if the disability never took place.

When healing is accomplished by human beings, firstly, the healing is only in regard to the future,4 and also, even afterwards, a trace [of the infirmity] remains.5 When, by contrast, the healing comes from “I G‑d am your healer,” the infirmity is removed as if it never was.