Judging prohibitory sentence as only conveying undesirability and the imperative one as only expressing desirability

Q: At times, a prohibitive statement merely indicates undesirability and an imperative statement may only indicate desirability. How is the intended meaning determined? For example, many religious texts express the prohibition of building, sitting, writing, treading, or leaning against graves. However, Imam Ahmad maintains that these acts are only undesirable (refer to "Zad Al-Mustaqna`", Chapter on Funerals). Similarly, menstruating and unmarried women's attendance at the religious celebration of the two Feasts is only desirable according to the commentator of "`Umdat Al-Ahkam", not obligatory.

A: All Praise is due to Allah Alone. Peace and blessings be upon His Messenger, his family, and Companions! To commence: The standard of judging these statements depends on the contexts related to commandments and prohibitions. If no presumptive evidence exists to turn the imperative into desirable or the prohibitory into merely undesirable, then the basic rule is that imperative statements indicate obligation and prohibitory statements denote the unlawful.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.