a limb”—to the condition of avoiding impurity among the conditions of prayer?

The answer is that the relevance is this: if one of his limbs were severed, then immediately reattached and healed back together, it would be pure; he would not be required to remove it when he wishes to pray.

Prayer is not valid in a graveyard or a toilet, …

His statement, “Prayer is not valid in a graveyard”: declaring it invalid entails that it is defective, because every act of worship is either valid or defective, with no middle state between them. In the Sacred Law, they are mutually exclusive opposites: once validity is negated, invalidity is established.

His statement, “prayer,” includes everything called prayer, whether obligatory or voluntary, and whether it involves bowing and prostration or not, because he said, “prayer.” Accordingly, it includes the funeral prayer, so it would not be valid in a graveyard. However, the evidence indicates that the funeral prayer is excepted, as we shall mention, Allah willing (1). Thus, what is meant by prayer here is every prayer other than the funeral prayer.

Is mere prostration permissible—for example, a prostration of Quranic recitation—if someone is reading in a graveyard and comes across a verse requiring prostration? This depends on the scholars’ disagreement concerning the prostration of recitation. Some hold that it is a prayer, while others hold that it is not a prayer (2).

Those who hold that it is not a prayer say that a person may perform the prostration of recitation in a graveyard. Those who hold that it is a prayer say that he may not (3).