פירוש על דברים 25:2

והפילו השפט AND THE JUDGE SHALL CAUSE HIM TO FALL DOWN — This teaches that one is not lashed whilst standing or sitting but only when bending (Makkot 22b).

והפילו השופט, he will stretch him out on the post. [The lashes are not applied when the victim is standing upright, but when he is at least inclined. (Makkot 22) Ed.]

אם בן הכות הרשע, "if the person found guilty (the wicked one) is convicted he is to receive 39 lashes, etc." The reason the Torah wrote the word בן with the vowel chirik instead of the customary vowel segol is that he who administers the lashes must evaluate if the victim is physically able to absorb these lashes without injury. In the event that the health of the individual in question cannot absorb the normal number of lashes, i.e. that he is not ben hakkot, he receives only as many lashes as are compatible with maintaining his level of health (compare Makkot 22).

כדי רשעתו במספר, “according to his wickedness, by a count.” Seeing that the vowel under the letter ב in the word במספר is a semi-vowel sheva, it is clear that that word belongs to the word ארבעים in the verse which follows. In other words: “the number is close to 40, but not precisely 40.” This is where our sages got the number 39 for the number of strokes to be administered. The deeper significance of this number 39 is that a dead person needs to be resurrected; a person who committed a sin and transgressed against the laws of his master is guilty of death. His soul is subject to the karet penalty. The penalty of 39 lashes substitutes for the death penalty and is equivalent to the dew (טל=39) which G’d is reputed to employ to bring the dead back to life (compare Chagigah 12). The Talmud Megillah 7 states that people who qualified for the karet penalty but have endured the penalty of מלקות instead are thereby saved from having to endure the karet penalty after their death. In other words, this corporal punishment is a form of atonement for a greater penalty. It is as if the guilty party had already received the טל של תחייה, the life-restoring dew in advance.
There is another reason for this number. The culpability for sins through trial on earth commences with age 13. The number of strokes administered is 39, i.e. three times the number 13. This equals the numerical value of the word טל. Culpability by the heavenly tribunal only commences with age 20. Three times 20 is 60. This is what Baba Metzia 85 refers to when it describes that Elijah (the apparition of Elijah traversing the earth) was struck with 60 brands of fire for having divulged celestial secrets to mortal man.
If the sages are in the habit of always referring to 40 lashes instead of to 39 lashes, or “40 minus one lashes,“ such as when they describe the various kinds of forbidden categories of work on the Sabbath as “40 minus one” (Shabbat 73), the reason is that they wanted to model their speech as closely as possible on the language of the Torah itself, seeing the Torah wrote ארבעים יכנו, “he shall strike him with 40 (lashes).” The reason the Torah adds the words כדי רשעתו, “in accordance with his wickedness,” is that the ferocity with which these lashes are administered depends on the severity of the sin for which it is administered (compare Ibn Ezra).

And behind him, in the amount befitting a double crime, etc. Thus there are three amounts befitting a crime, one at the front, i.e., a third at the front, and two measures from behind him. There are those who explain thatכדי רשעתו [which can be translated, “according to amount that makes him wicked”], is thirteen lashes, because a person is punishable when he reaches the age of thirteen. “Before him” mean opposite his heart, “behind him” on his back, [and he gets “the amount befitting a double crime” on his back] because those two measures are a fine.

בן הכות, “deserves to be punished by physical lashes;” the expression is similar to בן מות, “deserving of the death penalty,” the word בן here with the vowel chirik under the latter ב, is similar to the one in the name of Joshua, i.e. יהושע בן נון, “Joshua, son of Nun,” or אגור בן יקה, in Proverbs 30,1.

לפניו כדי רשעתו [AND THE JUDGE SHALL … SMITE HIM] IN FRONT ACCORDING TO HIS WICKEDNESS (כדי רשעתו may mean “as much as is sufficient for his wickedness”, i.e., for one part of his wickedness, רשעתו being singular) — in front (on his chest) corresponding to one part of his wickedness, and on his back corresponding to two parts: hence they (the Rabbis) derived that one must give him (anyone sentenced to lashes) two-thirds on his back and one third on his chest (Sifrei Devarim 286:6; Makkot 22b, 23a).

This is not vocalized במספר, etc. I.e., with a pasach under the ב'.

והכהו לפניו, “and he has to strike him in his presence.” The man carrying out the court’s judgment must do so in the presence of the judge who had convicted the sinner. (Compare Talmud, tractate Makkot folio 22.)

בְּמספר BY A NUMBER — but it (the word) is not punctuated בַּמספר by the number; this shows that it is connected with the following word, to read בְּמִסְפַּר ארבעים [“he shall smite him”] … by the number of forty, (i.e. by the number leading to forty), not, however, a full forty, but a number that leads up to the full total of forty, i.e., forty less one (Makkot 22a).

Rather, the number which concludes and completes up to forty, etc. I.e., one has to count and mention the number forty minus one; that is, one must not say “thirty-nine,” but “forty minus one.” The reason for [counting] this [way] is so that one does not forget and give him an additional lash, and transgress “lest he additionally flog him, etc.” Therefore he must say “forty minus one” in order for him to remember. This explains why Scripture mentions “forty,” and not thirty-nine.

כדי רשעתו, “according to the measure of his wickedness.” This sounds somewhat indefinite, as if the judge could impose different penalties of lashes for different sins. The conclusion of the Talmud is that under no circumstances must the number 39 be exceeded. Possibly, the degree of force used to apply the lashes varies with different sins.