No Armor For the Back

In the Valley of Humiliation, poor Christian was hard put to it; for he had gone a little way before he espied a foul fiend coming over the field to meet him: his name is Apollyon. Then Christian began to be afraid, and to wonder whether to go back or to stand his ground. But he remembered that he had no armor for his back, and therefore thought that to turn around might give Apollyon greater ease to pierce him with darts; therefore he resolved to venture and stand his ground.

–John Bunyan, from The Pilgrim’s Progress