Because the people had not repented when given the opportunity, Yahweh confirms that they have moved away from him. Typically Yahweh’s vengeance is expressed toward the covenant people’s enemies. In this case, it is directed toward the Nephites themselves because of their disobedience and hard-heartedness.
Reference: Romans 12:19 clearly inspired the opening phrase: “Dearly beloved, avenge not yourselves, but rather give place unto wrath: for it is written, Vengeance is mine; I will repay, saith the Lord.” As we have seen in other cases, although the meaning is similar, the phrase is used in a different context.
Romans references Deuteronomy 32:35: “To me belongeth vengeance, and recompence; their foot shall slide in due time: for the day of their calamity is at hand, and the things that shall come upon them make haste.”
Mormon introduces this passage as a revelation in verse 14: “the voice of the Lord came unto me, saying.… ” Moroni quotes this same combination of words as part of a longer passage that he identifies as scripture (Morm. 8:20).