Sifrei Devarim 254

¹(Devarim 23:10) "When you go out, an encampment against your enemies, then you shall guard yourself against every evil thing." "when you go out, an encampment": When you go out, go out in an encampment (i.e., en masse). ²"against your enemies": (Keep it in mind that you are going out) against your enemies , (and act accordingly). ³"then you shall guard yourself against every evil thing ": I might think that this refers to (the need for circumspection vis-à-vis) cleanliness, uncleanliness, and tithes; it is, therefore, written ( Ibid . 15) "and He shall not see in you a thing of nakedness" ( ervah ). This tells me only of " ervah ." Whence is included (in the need for circumspection) idolatry, bloodshed, and blasphemy? From "then you shall guard yourself against every evil thing." Just as " ervah " is distinct in that it is something for which the Canaanites were exiled and because of which the Shechinah is removed, so, all such things (are included). ⁴"evil thing " (" davar ") includes even slander (" dibbur ra ").