The Complete Poetical Works of Oliver Wendell Holmes/Joseph Warren, M. D.

Trained in the holy art whose lifted shield
  Wards off the darts a never-slumbering foe,
  By hearth and wayside lurking, waits to throw,
Oppression taught his helpful arm to wield
The slayer's weapon: on the murderous field
  The fiery bolt he challenged laid him low,
  Seeking its noblest victim. Even so
The charter of a nation must be sealed!
  The healer's brow the hero's honors crowned,
From lowliest duty called to loftiest deed.
  Living, the oak-leaf wreath his temples bound;
Dying, the conqueror's laurel was his meed,
Last on the broken ramparts' turf to bleed
  Where Freedom's victory in defeat was found.