Sam Quotes in With the Old Breed
This standard procedure in combat on the front line was based on a fundamental creed of faith and trust. You could depend on your buddy; he could depend on you. It extended beyond your foxhole, too. We felt secure, knowing that one man in each hole was on watch through the night.
Sam had betrayed that basic trust and had committed an unforgivable breach of faith. He went to sleep on watch while on the line. As a result his buddy died and another man would bear the heavy burden of knowing that, accident though it was, he had pulled the trigger.