Numeri 1:3

From twenty years old and upward, all that are able to go forth to war in Israel: thou and Aaron shall number them by their armies.

Ver. 3. All that are able.] The people perceiving how many hundred thousand strong they were, might go on with more courage against their enemies. It is an ancient custom in Scotland, in cases of importance, to command the fire cross to be carried; that is, two fire brands to be set in fashion of a cross, and pitched upon the point of a spear, and proclamation is thereupon made, that all men, above sixteen years of age and under sixty, shall come into the field to advance against the common enemy. a

a Sir John Heywood, in the Life of King Edward VI.