David Brainerd was pursued by unearthly adversaries who were resolved to rob him of his reward. He knew he must never take off his armor, but lie down to rest with his corselet laced. The stains that marred the perfection of his lustrous dress and the spots of rust on his gleaming shield are imperceptible to us, but they were to him the source of much sorrow and ardency of yearning.

from The Life of David Brainerd –