Commento su Esodo 21:19

על משענתו (lit., with that on which he relies) — i. e. his former healthy state and vigour (Mekhilta d'Rabbi Yishmael 21:19:1; cf. Onkelos).

IF HE RISE AGAIN, AND WALKS ABROAD ‘AL MISH’ANTO’ — “in his former healthy state and vigor.” This is Rashi’s language. And Rabbi ibn Ezra said that the reason why this word [which means literally: “support”] is used, is to tell us that he must not be dependant upon others for the ability to walk, like an invalid, but must walk by himself;¹³²Thus according to Rashi mish’anto is “his physical strength;” according to Ibn Ezra, it is “his leaning” or “support.” Ramban will proceed to explain it in its literal sense — “on his staff.” Almost all translations follow Ramban’s interpretation. only then shall he that smote him be quit from prison.
In my opinion, mish’anto is to be understood in its literal sense, [a staff], just as in the verses: every man with ‘mish’anto’ (his staff) in his hand for old age;¹³³Zechariah 8:4. ‘mish’eneth’ (the staff) of this bruised reed.¹³⁴II Kings 18:21. Scripture is thus stating that if the injured person’s health improves sufficiently to enable him to go out walking as he wishes in the streets and in the broad ways¹³⁵Song of Songs 3:2. with his staff, like those healed from some prolonged disabling injury, then shall he that smote him be quit; and it further teaches us that even if the injured man is careless later about his health and dies after that in his weakness, the assailant is free from the death penalty. Scripture says and he walketh abroad because it speaks of the customary way of life, for injured men who were laid up in bed do not go out walking again until their wounds have healed and they are out of danger, this being the sense of the phrase, and he walketh abroad, because if he just gets up and walks in his house on his staff, and then dies, the assailant is not free [from the death penalty].
In the words of the Mechilta:¹³⁶Mechilta here on the Verse. “If he rise again and walketh. I might think this means within the house; Scripture therefore says, abroad. But from the word abroad I might think that even if he was wasting away [the assailant is still free from punishment]; Scripture therefore says, if he rise again.” This explanation too is very correct, that Scripture should be saying that if the injured man gets up completely from his bed and goes steadily outside — without having to go back to his bed when returning from outside, as is the way of those who continue to waste away — even though he is weak and has to lean upon a staff, the assailant shall be let off. In general all this is to be interpreted as being figurative, language expressing people’s practical conduct, and the basic rule is that he must have been assessed as being capable of recovery. This is why Onkelos translated al mish’anto: al boryeih (in his healthy state).

רק שבתו יתן ורפא ירפא, he shall only pay for loss of income and cause him to be cured completely. This means that even if the victim has regained the ability to get around unassisted but he cannot yet pursue his occupation, the attacker has to continue payments for loss of income. The same applies to continued medical supervision of the victim if the latter deems same as necessary.