when an act of worship cannot be performed except in conjunction with something prohibited, performing it in that manner is preferable to abandoning it. All the established principles support this. Someone in a state of major ritual impurity following sexual activity who has neither water nor earth must also pray, according to the better-known of the two scholarly views, because he is unable to purify himself. Menstruation, however, is incompatible with prayer under all circumstances, because there is no need to pray during menstruation: the recurrence of equivalent prayers suffices.

By contrast, the obligation to perform Hajj and its circumambulation does not recur. If it were invalid despite a valid excuse, it would necessarily be invalid altogether. The established principles show that when an act of worship can only be performed with a valid excuse, it is valid and discharges the obligation despite that excuse, unlike when it is performed without such an excuse. It has already become clear that a menstruating woman has no valid excuse for praying during menstruation, since the recurrence of equivalent prayers outside her menstrual days suffices her. Circumambulation is different: if she can perform it only during menstruation, she has no equivalent act that would render it unnecessary. She is therefore permitted to perform it in that state, just as other conditions of worship are waived when she cannot fulfil them.

The third proof:

It may be argued that this is one form of purification, so its requirement is waived when one is unable to fulfil it, just as with other forms of purification. If she were experiencing non-menstrual bleeding and could circumambulate only in a state of continuous ritual impurity, she would circumambulate by scholarly agreement. There is a well-known disagreement among scholars as to whether ablution is obligatory for her. This involves praying both in a state of ritual impurity and while bearing physical impurity. Likewise, if someone in a state of major ritual impurity following sexual activity, or someone in a state of minor ritual impurity, has no access to either water or earth, he prays and circumambulates according to the stronger of the two scholarly views.

The fourth proof is to say:

This is a condition of circumambulation, and so it is waived