9. When the host goeth forth. What he had taught with respect to the preservation of purity at home, and in time of peace, he now extends to times of war also, so that they might keep themselves clean from all defilement even in the midst of the clang of arms. We know how greatly laws are disregarded during war, when all things are under the control of violence rather than reason; and we know that much license is wont to be given to soldiers, which would be by no means tolerated in peace. God would remedy this evil by requiring the Israelites to aim at the same purity in war as in peace; for this is a special law which forbids their being dissolute and unruly in war-time, as He has before condemned all impurity in general, as if He had said, that under no pretext would they be excusable, if they neglect the duty of cultivating habits of purity. For He does not command them to be cautious in the army and in the camp, as if they might sin with impunity when at home, but admonishes them that God would by no means excuse them although they should allege the necessity of war. Much more would the crime be aggravated, if they should pollute themselves in peace and when their minds were calm. Whence we gather that it is vain to catch at empty excuses for the violation of God’s commands in any respect; for, however difficult the performance of duty may be, still God never resigns His rights. Now, if war, which seems to dispense with laws, does not excuse crime, much greater, as I have said, shall their guilt be accounted, who in a tranquil condition of life are licentiously carried away by sin.

10. If there be among you. He enumerates two kinds of pollution, whereby the Israelites may know what is meant by their keeping from the “wicked thing.” First, He pronounces to be unclean, and casts out of the camp those who may have had a filthy dream, until they shall have washed themselves in the evening. Secondly, He forbids them to defile the camp with what passes from the bowels; and not only this, but, even when they have gone outside the camp, He commands them to bury their excrement beneath the earth, lest any filthiness should appear. Yet it is probable that, by synecdoche, everything is referred to which rendered men unclean and polluted. But Moses, speaking as to soldiers, considered it sufficient to tell them briefly, that although they might be occupied with war, cleanliness must still be attended to. By “what chanceth at night,” all are agreed in understanding a flow of semen; from whence we infer how greatly impurity defiles a man, since uncleanness is contracted even from foul dreams. As to the second part, some desire to appear quick and clever by attacking Moses, because he has introduced among the precepts of holiness, that none should relieve his bowels in the camp. Forsooth, they say, the smell might offend the nostrils of God! But their silly petulance is easily rebutted; for God would by such rudiments keep His ancient people in the way of duty, lest liberty even in the most trifling things should lead them onwards to audacity. If they had been permitted to defile every part of the camp, the people would presently have been hardened against filthiness of every sort. Thus they were held back by this rein, that they might more earnestly apply their minds to spiritual integrity. They also are mistaken who suppose that this was a sanitary precaution, lest the smell should produce diseases, and be injurious to their bodily health. For Moses plainly declares that he not only had regard to what was wholesome, or even to what was decent in the eyes of men; but rather that he would accustom the people to abhor uncleanness, and to keep themselves pure and unpolluted — for he adds, that God presided in the camp, to protect them from the power and assaults of their enemies; and that they should fear, lest, if they should contaminate the camp, He would be offended with their filthiness and forsake them. The sum is, that when they have need of God’s assistance, and are engaged in war against their enemies, the pursuit of holiness must not be omitted or neglected even in the midst of arms.