Mishneh Torah, Forbidden Intercourse 6-8

Sugya Map

• Issue: The ontological vs. functional status of uterine blood (Niddah vs. Zavah).
• Nafka Mina: Whether the impurity is intrinsic to the blood or contingent on the temporal window of the cycle.
• Primary Sources: MT Hilchot Issurei Biah 6:1; Niddah 96b; Leviticus 15:19–28.

Text Snapshot

• MT 6:1: "דם הנידה... ודם טוהר... כולם דם אחד הוא ומעין אחד הוא. ובזמנים בלבד הוא שישתנה דינו."
  • Nuance: Rambam insists on the physical unity of the fluid (ma'ayan echad) to preempt any "biological" essentialism. The din (legal status) is purely a function of zman (timing/circumstance).

Readings

• Rambam (MT 6:1): The "days of Niddah" and "days of Zivah" are fixed, recurring cycles (7/11) independent of actual bleeding.
• Ramban (in Hilchot Niddah): Disputes this; he argues these categories are reactive to the woman’s specific physical history, not an abstract calendar.

Friction

• Kushya: If, as Rambam asserts, the blood is physically identical, why does the Torah mandate different purity processes (e.g., Korban for a Zavah vs. simple immersion for a Niddah)?
• Terutz: The impurity is not a physical property of the blood but a Gezeirat HaKatuv (decree) mapping ritual status onto the woman’s temporal state. As Steinsaltz notes: "שהטומאה נקבעת לפי זמן הראייה" (The impurity is determined by the time of sighting).

Intertext

• Leviticus 15:25: "When a woman will have a flow of blood for many days..." – The shift from Niddah to Zavah is triggered by the deviation from the "usual" time (lo b'et niddatah).
• SA Yoreh De'ah 183: Reflects the historical consensus that despite Rambam’s rigor, the "Chumra d'Rabbi Zeira" (counting 7 clean days for any sighting) effectively bypassed the need to resolve the technical Niddah/Zavah classification in practice.

Psak/Practice

• Meta-Psak: The Rambam’s systematic approach is a masterclass in legal classification, but post-Talmudic psak leans toward the Chumra (stringency) of Rabbi Zeira. We treat all blood as potentially Zavah blood to avoid the dangerous necessity of calculating 11-day cycles in real-time.

Takeaway

Ritual status is a temporal construct, not a biological one. When the law defines a "pure" or "impure" window, it governs the relationship between the person and the sanctity of the Temple, regardless of the blood's physical consistency.