Rashi notes that here the Torah spells the word לֻחֹת, luchos, tablets—without the letter “ו” that emphasizes the plural—rendering the word readable as לֻחַת, luchas—a singular tablet. Rashi explains that the Torah employs this unusual spelling to highlight that the two Tablets were identical—as though they are one and the same.
Though the simple meaning of Rashi’s explanation is that both Luchos were of equal size, his words can also be understood homiletically as alluding to the spiritual equivalence of the Tablets’ contents.
Inscribed in the Luchos were the Ten Commandments, in the order they were said, five on each tablet. The first five commandments are principally positive commandments: faith in the existence of G-d, observance of Shabbos and honoring one’s parents. Conversely, the last five commandments are prohibitions: do not murder, do not commit adultery, etc.
Accordingly, the Torah’s spelling of the word luchos in singular form teaches us that refraining from that which the Torah prohibits is equally as constructive as fulfilling the positive commands. For the bond with G-d that we create with each mitzvah we fulfill is equal, whether we are observing that which He commands us to do, or abstaining from that which He prohibits us from doing.
In addition, equating the positive commands inscribed in the first Tablet with the prohibitions inscribed in the second Tablet highlights the active aspect of the mitzvos’ fulfillment that is common to both the commands and the prohibitions—the study of their detailed laws as they are found in the Torah.
—Sefer Hasichos 5751, vol. 1, pp. 369–370
