Al-Athram transmitted from Ahmad that he said: “The senior Companions of the Messenger of Allah—may Allah’s blessings and peace be upon him—maintained that al-aqrāʾ are the menstrual periods.” He likewise narrated from al-Shaʿbī that this was the statement of eleven—or twelve—Companions of the Messenger of Allah (peace and blessings be upon him).

As for Ahmad ibn Ḥanbal himself, the reports from him diverge. One narration relates that he used to say they are the periods of purity, following the position of Zayd ibn Thābit, Ibn ʿUmar, and ʿĀʾishah. “I have now suspended judgment,” he later remarked, “because of the opinions of Ibn Masʿūd and ʿAlī that they are the menstrual periods.”

The practical difference between the two schools is this: whoever holds that they are periods of purity believes that when a revocably divorced woman enters her third menstrual flow, her husband’s right of retrieval ceases and she becomes lawful for other suitors. Those who hold that they are the menstrual flows, however, deem her lawful only after the third menses is completed.

The root of the disagreement lies in the shared usage of the word quruʾ: in classical Arabic it can refer, with equal propriety, either to the flow of blood or to the intervals of purity. Each side has therefore sought textual evidence showing that, in the Qur’ānic verse, the word bears the meaning it favors.

The scholars who say it designates the periods of purity argue that the plural form qurūʾ is exclusive to quruʾ meaning purity, whereas when quruʾ means menses its plural is aqrāʾ, not qurūʾ—a point they cite on the authority of Ibn al-Anbārī. They further contend that ḥayḍah (menstruation) is grammatically feminine whereas ṭuhr (purity) is masculine; had quruʾ in the verse meant menses, the feminine tāʾ could not have remained in the plural, for that ending does not persist in the plural of a feminine noun under ten. They also adduce etymology: quruʾ is derived from qarraʾtu ’l-māʾ fī ’l-ḥawḍ, “I collected the water in the basin,” so the time when the blood ‘collects’ is precisely the period of purity. This, they claim, is their strongest proof from the plain wording of the verse.

Those who take quruʾ to mean menses reply that the Almighty’s words, “three quruʾ” (Q 2:228), plainly require the completion of each quruʾ, for the term cannot be applied to part of a period except figuratively. If, however, quruʾ were understood as periods of purity, the waiting period could—on that view—amount to merely two full periods and a portion of a third, since they count the purity in which the divorce is pronounced even if most of it has elapsed; in that situation the designation “three” would itself be figurative. Yet the word “three” in the verse clearly implies the full completion of every quruʾ, and that only accords with defining quruʾ as the menstrual periods, for there is unanimous agreement that a menses during which the divorce is given is not counted toward the waiting period. Thus both sides possess arguments of equal weight from the lexical angle, and the discerning scholars have concluded that the verse itself is ambiguous on this point and that the decisive evidence must be sought elsewhere.

Among the strongest supports for the view that quruʾ are periods of purity is the previously cited ḥadīth of Ibn ʿUmar, together with the Prophet’s—peace and blessings be upon him—words: “Order him to take her back until she menstruates, then becomes pure, then menstruates, then becomes pure; after that he may divorce her, if he wishes, before touching her. That is the waiting period which Allah has commanded for women when they are divorced.”

They said: