Commento su Levitico 26:20

ותם לריק כחכם AND YOUR STRENGTH SHALL BE SPENT IN VAIN — Behold, if a man does not toil in his field — neither tills, nor sows, nor weeds it, nor clears away the thorns, nor hoes it, and then at harvest time blight comes and strikes it (the field, i. e. destroys that which sprung up of itself), surely it does not matter much (he does not take it to heart). But if a man has toiled — he has ploughed, sown, weeded, cleared away the thorns and hoed it, and then blight comes and strikes it, surely then the teeth of that man become blunt! (a figurative expression for becoming speechless, terror-stricken) (Sifra, Bechukotai, Chapter 5 4).

ותם לריק כחכם, "and your strength will be spent in vain." The meaning is the same as if the Torah had written ותם כחכם לריק, meaning that your entire efforts will be to no avail. The Torah had to tell us this as the power of destructive forces often is only partially effective.

כחכם, for the earth will no longer lend you its strength.

Who does not weed, nor harvest. נוכש is to gather weeds from among the seedlings, כסח is to harvest, and עודר is to dig.

ותם לריק כוכחם, “your strength will be spent in vain.” This is the opposite of verse 5, ובציר ישיג את זרע, “and the grape harvest will last until it is time to sew again.” We find the expression כח used in connection with harvest in Genesis 4,12 when G-d tells Kayin that the earth will not continue to give its strength to him as it had cooperated with him in hiding his brother’s blood. This is the fourth curse.

ולא תתן ארצכם את יבולה — This means, the earth shall not yield even as much as you brought to it at sowing-time (יבולה as passive participle with suffix of יבל “to bring”, may denote: that which is brought to it) (Sifra, Bechukotai, Chapter 5 4).

Behold the teeth of such a one are set on edge. Thus “Your strength will be exhausted in vain” means after this labor and effort, since then the teeth of such a one are set on edge. If “your strength” meant their money that comes from [exerting] strength [effort], the verse need not have mentioned this, as Scripture had already written, “I will make your heavens like iron,” and probably they exhausted [their money] in vain. (Gur Aryeh) You also cannot say it means that their physical strength will be exhausted, because if so it need not have said “in vain,” but [simply], “Your strength will be exhausted.”

ולא תתן ארצכם את יבולה, “your land will not yield its harvest.” This is the fifth curse.

ועץ הארץ AND THE TREE OF THE GROUND [SHALL NOT YIELD] — This implies that even from the very earth a curse will rest upon it — that it will not bring its fruits to development at the time when they should develop (Sifra, Bechukotai, Chapter 5 4).

What you bring to it. Rashi is answering the question: Why is it written “your land”? It should have written “The land will not yield,” as above in the blessing (verse 4), “The earth shall give forth its produce.” Therefore, “your land” implies even what you bring to it of your own at the time of seeding; even this it will not yield. Alternatively, Rashi infers this from the word יבולה (produce), which connotes moving something (מוביל), [implying] that he brings [seed]. (Re’m)

לא יתן פריו, “the trees will not yield their fruit.” This is the sixth curse. According to Rashi, this is a twofold curse. (as it refers both to the trunks of the trees and their fruit)

לא יתן serves as the verb with what precedes and with what follows — with “tree” and with “fruit”. Thus we obtain a second sense —

Even from the very earth a curse will be upon them. Rashi is answering the question: It should have said “And the tree will not give forth its produce”! Why write “of the land”?

לא יתן פריו IT WILL NOT GIVE ITS FRUIT — when it does produce fruit, it will cast its fruits (Sifra, Bechukotai, Chapter 5 4). This gives two curses, and so you have here seven punishments in all.