What is the required duration for *istibra'* upon acquiring an enslaved woman through legal means such as sale, gift, or inheritance?

Primary text

It is obligatory to seek *istibra'* from any woman acquired by ownership—be it through sale, gift, inheritance, or other means—before having intercourse with her. This requirement applies regardless of whether she is a virgin or previously married, young or old, capable of childbearing or not. This view is held by Al-Hasan, Ibn Sirin, and the majority of scholars, including Malik, Al-Shafi'i, and the proponents of the Raisoneur School (Ashab Al-Ra'y). The period for establishing purity is completed by one menstrual cycle if she menstruates, by delivery if she is pregnant, or by the passage of three months if she is post-menopausal or has never menstruated.