כֵּיצַד מַלְקִין אֶת הַמְחֻיָּב מַלְקוֹת. כְּפִי כֹּחוֹ שֶׁנֶּאֱמַר (דברים כה ב) "כְּדֵי רִשְׁעָתוֹ בְּמִסְפָּר". וְזֶה שֶׁנֶּאֱמַר (דברים כה ג) "אַרְבָּעִים" שֶׁאֵין מוֹסִיפִין עַל הָאַרְבָּעִים אֲפִלּוּ הָיָה חָזָק וּבָרִיא כְּשִׁמְשׁוֹן. אֲבָל פּוֹחֲתִין לַחַלָּשׁ שֶׁאִם יַכֶּה לַחַלָּשׁ מַכָּה רַבָּה בְּוַדַּאי הוּא מֵת. לְפִיכָךְ אָמְרוּ חֲכָמִים שֶׁאֲפִלּוּ הַבָּרִיא בְּיוֹתֵר מַכִּין אוֹתוֹ שְׁלֹשִׁים וְתֵשַׁע שֶׁאִם יוֹסִיף לוֹ אַחַת נִמְצֵאת שֶׁלֹּא הִכָּהוּ אֶלָּא אַרְבָּעִים הָרְאוּיוֹת לוֹ:
How are lashes administered to a person liable to receive them? According to his strength, as indicated by Deuteronomy 25:2: "According to his wickedness by number." The number 40 stated in the following verse is mentioned to teach that more than 40 lashes are never administered even if the person is as healthy and as strong as Samson. When, by contrast, a person is weak, the amount of lashes is reduced. For if a weak person is given many lashes, he will certainly die. Therefore our Sages said: that even a very healthy person is given only 39 lashes. For if accidentally an extra blow is administered, he will still not have been given more than the 40 which he was required to receive.
