A flaming sword is a sword glowing with flame by some supernatural power. Flaming swords have existed in legend and myth for thousands of years.
According to the Bible, a Cherub (or the archangel Uriel in a some traditions) with a flaming sword was placed by God at the gates of Paradise after Adam and Eve were banished from it (Genesis 3:24).
Eastern Orthodox tradition says that after Jesus was crucified and resurrected, the flaming sword was removed from the Garden of Eden, making it possible for humanity to re-enter Paradise.
A flaming sword with immense destructive power appears in Norse mythology. It is said to be wielded by Surtur, the leader of the giants of Muspelheim.