تعریف و معنای "a matter of life and death"

What is the origin of the idiom "a matter of life and death" and when to use it?

The idiom "a matter of life and death" is used to emphasize the extreme seriousness and significance of a situation, decision, or action, where the outcome could determine whether someone lives or dies. This expression does not have a specific historical origin but is rooted in the fundamental importance of life and survival.