Deuteronomy 13 · a question people ask
What if the report about the city wasn't true?
The chapter puts the checking first. "If you hear about one of your cities" (13:12), then "you shall inquire, investigate, and ask diligently. Behold, if it is true, and the thing certain, that such abomination was done among you" (13:14), and only then does 13:15 follow. Deuteronomy says the same in the law about anyone found serving other gods: "then you shall inquire diligently. Behold, if it is true, and the thing certain" (17:4), and adds, "At the mouth of one witness he shall not be put to death" (17:6). It also says what happens to a false witness: "the judges shall make diligent inquisition; and behold, if the witness is a false witness, and has testified falsely against his brother, then you shall do to him as he had thought to do to his brother" (19:18-19). In this chapter, 13:15 follows only "if it is true, and the thing certain" (13:14); the chapter gives no more detail than that about how the inquiry was made.
The verses
“If you hear about one of your cities, which the LORD your God gives you to dwell there, that certain wicked fellows have gone out from among you and have drawn away the inhabitants of their city, saying, “Let’s go and serve other gods,” which you have not known, then you shall inquire, investigate, and ask diligently. Behold, if it is true, and the thing certain, that such abomination was done among you, you shall surely strike the inhabitants of that city with the edge of the sword, destroying it utterly, with all that is therein and its livestock, with the edge of the sword.”
“If an unrighteous witness rises up against any man to testify against him of wrongdoing, then both the men, between whom the controversy is, shall stand before the LORD, before the priests and the judges who shall be in those days; and the judges shall make diligent inquisition; and behold, if the witness is a false witness, and has testified falsely against his brother, then you shall do to him as he had thought to do to his brother. So you shall remove the evil from among you.”