Sotah 17B

הדיפתרא, אלא על המגילה, שנאמר: ״בספר״.

diftera, a hide that is only partially processed, as it is salted and treated with flour but not gallnuts; rather, it must be written only on a scroll of parchment, as it is stated: “And the priest should write these curses in a scroll” (Numbers 5:23).

ואינו כותב לא בקומוס ולא בקנקנתום, ולא בכל דבר שרושם, אלא בדיו, שנאמר: ״ומחה״, כתב שיכול למחות.

And the scribe may not write with gum [komos], and not with iron sulfate [kankantom], nor with any substance that makes a mark and cannot be completely erased, but only with ink made from soot, as it is stated in the continuation of the same verse: “And he should blot them out into the water of bitterness” (Numbers 5:23). This indicates that the scroll must be written with a writing that can be erased in water.

גמ׳ אמר רבא: מגילת סוטה שכתבה בלילה ⁠— פסולה. מאי טעמא ⁠— אתיא ״תורה״ ״תורה״. כתיב הכא: ״ועשה לה הכהן את כל התורה הזאת״, וכתיב התם: ״על פי התורה אשר יורוך ועל המשפט״, מה משפט ביום ⁠— אף מגילת סוטה ביום.

Talmud: Rava says: A scroll of a sota that one wrote at night is unfit. What is the reason for this? It is derived by verbal analogy between one instance of the word “law” and another instance of the word “law.” It is written here, with regard to a sota: “And the priest should execute upon her all this law” (Numbers 5:30), and it is written there, with regard to judgment: “According to the law, which they should teach you, and according to the judgment, which they should tell you” (Deuteronomy 17:11). Just as judgment may be done only by day, so too the scroll of a sota may be written only by day.

כתבה למפרע ⁠— פסולה, דכתיב: ״וכתב את האלות האלה״, כי דכתיבא.

If one wrote the scroll out of sequence, it is unfit, as it is written: “And the priest should write these curses in a scroll” (Numbers 5:23). They must be written in the scroll just as they are written in the Torah.