No plainsman needs to be told that a man should not lie near a fire if there is danger of an enemy creeping up on him, and that above all a man should not put himself in a position where he can be ambushed at dawn.
 Theodore Roosevelt, Theodore Roosevelt; an Autobiography (1913). copy citation

Context

“Then I picketed the mare, slept where I was without a fire until the first streak of dawn, and then pushed on for a couple of hours before halting to take breakfast and to let the little mare have a good feed. No plainsman needs to be told that a man should not lie near a fire if there is danger of an enemy creeping up on him, and that above all a man should not put himself in a position where he can be ambushed at dawn. On this second day I lost the trail, and toward nightfall gave up the effort to find it, camped where I was, and went out to shoot a grouse for supper. It was while hunting in vain for a grouse that I came on the bear and killed it as above described.” source