What is the clarification of the jurisprudential rule: "Necessities permit the prohibited, and needs permit..." etc.?

"Necessities permit the forbidden" is a jurisprudential rule derived from the Almighty's saying: (except for that to which you are compelled). Its meaning is that what is forbidden by Islamic law becomes permissible out of necessity. Examples include: permitting the eating of carrion during famine, moistening a morsel with wine for one who chokes and finds nothing else, and permitting a word of disbelief for one who is forced to utter it under threat of death or severe torture. This rule is a subsidiary of the principle: "Harm is to be removed."