What is the ruling when divorce is conditioned upon the negation of an impossible act?
Chapter on Explicit Divorce and Others
Al-Mughni
Book of Divorce
Primary text
If the husband conditions divorce upon the wife *not* performing an impossible act (e.g., 'You are divorced if you do not kill the dead' or 'if you do not ascend to heaven'), the divorce occurs immediately. This is because the condition rests upon a negation that is known to be true (non-occurrence) in both the present and future, causing the divorce to take effect immediately, similar to conditioning divorce on the non-occurrence of a possible event, such as 'if I do not sell my slave' and the slave dies.
Supporting text
When divorce is stated with the intention of performing an impossible future act, such as 'I will surely drink the water in this jug when there is no water in it,' the divorce occurs immediately based on the aforementioned reasoning. However, Abu Al-Khattab narrated from Al-Qadi that no divorce occurs, drawing an analogy to one who swears an oath to ascend to heaven or fly, who is not considered to have broken their oath (i.e., not incurring expiation for breaking an oath).