a matter of life and death

a situation that is not to be ignored or understimated

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.

The doctor stressed that taking the prescribed medication was a matter of life and death for the patient.
In emergency situations, the ability to remain calm and focused can be a matter of life and death for first responders.
The survival skills they learned in the wilderness were a matter of life and death during their expedition.
The pilot's quick thinking and precise actions turned a potentially fatal aircraft malfunction into a matter of life and death averted.
When facing a natural disaster, having an evacuation plan in place becomes a matter of life and death for residents in vulnerable areas.