“He who lives by the sword, dies by the sword.”
Jesus Christ (The Bible, Matthew 26:52)
“Live by the sword, die by the sword” is a metaphorical expression meaning that living one’s life in a certain way will, in the end, affect one’s destiny. The proverb comes from the Gospel of Matthew, verse 26:52, which describes a disciple (identified in the Gospel of John as Peter) drawing a sword to defend against the arrest of Jesus in the Garden of Gethsemane, but is rebuked by Jesus, who tells him to sheath the weapon:
Then said Jesus unto him, Put up again thy sword into his place: for all they that take the sword shall perish with the sword.
While a common modern interpretation means “those who live by violence will die by violence”, suggesting nonviolence or pacifism as an alternative, it is also used for a variety of situations which contain an element of poetic justice.