In sum, the root of the disagreement lies in the following question: Are the conditions that the Law has laid down for a Sunnah-compliant divorce conditions of validity and legal effect, or merely conditions of perfection and completion?
• Whoever holds that they are conditions of validity says that any divorce pronounced without fulfilling those conditions does not take effect.
• Whoever regards them as conditions of perfection says that the divorce does take effect, though it is recommended that it be carried out in its complete, ideal form. For this reason, anyone who affirms that the divorce is effective yet still forces the husband to revoke it has fallen into a contradiction—reflect on that.

Second issue: Must the husband be compelled to take her back, or is compulsion unnecessary?
• Those who take the directive at its face value—which, according to the majority, denotes obligation—say he must be compelled.
• Those who consider, as explained, that the divorce has already taken place, maintain that the directive is only a recommendation.

Third issue: After being compelled, when may he pronounce a new divorce?
Those who stipulate that he must keep her until she becomes pure, menstruates once more, and then becomes pure again base this on the explicit wording of the previously cited ḥadīth of Ibn ʿUmar. They argue that this allows the revocation to become effective through intercourse in the purity that follows the next menses; for if he were to divorce her in that very purity, no waiting period would remain for any subsequent divorce, and the case would resemble divorcing a woman before consummation.
In brief, they say that one of the conditions for a valid revocation is the presence of a period in which intercourse is lawful. On this reasoning, a Sunnah-compliant divorce requires that he divorce her in a purity in which he has not had intercourse during the immediately preceding menses—one of the conditions Malik lists for a Sunnah divorce, as reported by ʿAbd al-Wahhāb.
Those who do not require this leaned on the narration transmitted by Yūnus ibn Jubayr, Saʿīd ibn Jubayr, Ibn Sīrīn, and others from Ibn ʿUmar, in which he said: “He should take her back, and when she becomes pure he may divorce her if he wishes.” They explain that the husband was ordered to revoke as a disciplinary measure because he had divorced at a time when divorce is disapproved; once that period is past, he may divorce in a manner that is not objectionable. Their divergence thus stems from conflicting reports on the matter and from differing notions of the underlying rationale.

Fourth issue: When may compulsion be applied?
Malik holds that the husband may be forced to take her back throughout the entire waiting period, for that is the span during which revocation is possible. Ashhab, however, followed the literal sense of the ḥadīth: “Tell him to take her back until she becomes pure,” which indicates that the revocation occurred during the same menses. He further contends that the command aims to prevent her waiting period from being prolonged, since a divorce pronounced during menstruation is unanimously not counted toward the ʿiddah. If, therefore, we required him to revoke outside that menses, her waiting period would only be lengthened. On this reasoning it should be permissible to pronounce the divorce in the purity immediately following the menses.
Thus, the cause of their disagreement is identical to their difference over the rationale behind the command to revoke.