命を捨てる
the act of sacrificing one's life
to do something at the cost of one's own life
to be able to lay down one's life for something
I had a narrow escape―I was snatched from the jaws of death―It was a close shave―a close call.
貴命を奉じて
to save one's life―save one from death―(殺そうと思った人の命なら)―spare one's life