Fight, Bleed and Fight Some More

I am currently reading Phantastes by George McDonald.  The following is the epigraph at the beginning of chapter seven and is taken from “Ballad of Sir Andrew Barton”:

Fight on, my men, Sir Andrew sayes,
A little Ime hurt, but yett not slaine;
Ile but lye down, and bleede awhile,
And then Ile rise and fight againe.

One is permitted to lay down and bleed awhile as long as he gets back into the fight—a soldiers rule of life.