Matthew Poole and continuators on Deuteronomy 23:9

9 When the host goeth forth against thine enemies then keep thee from every wicked thing

Then especially take heed, because that is a time and state of confusion and licentiousness, when, as one said, the Laws of God and Man cannot be heard for the noise of arms; and because the success of thy arms and enterprizes depends upon Gods blessing, which wicked men have no reason to expect; and because thou dost then carry thy life in thy hand, and therefore hast need to be well prepared for Death and Judgment.