Exodus 20:5 (King James Bible) for I the LORD thy God am a jealous God visiting the iniquity of the fathers upon the children
One may wonder here if the plural iniquities might be an error for the singular iniquity, the reading of the King James Bible. The Masoretic Hebrew text, which serves as the basis for the King James translation, has the singular iniquity here in Exodus 20:5. But interestingly, the Septuagint Greek reads in the plural (literally, “sins of fathers”) in its translation of Exodus 20:5. Moreover, in the two passages where Abinadi refers to the Lord visiting the people of Noah to punish them, the text uses the plural iniquities rather than the singular iniquity; in fact, the first of these paraphrases Exodus 20:5:
Thus in the Book of Mormon (including here in Mosiah 13:13, a direct citation of Exodus 20:5), the text prefers the plural iniquities when referring to the Lord visiting his people in anger. Similarly, in two Isaiah quotations, the Book of Mormon has the plural iniquities instead of the singular iniquity in the King James text—namely, in 2 Nephi 24:21 and Mosiah 14:6 (see the discussion under those two passages). Thus the critical text will maintain the plural iniquities here in Mosiah 13:13.
Summary: Retain the plural iniquities in Mosiah 13:13, the reading of the printer’s manuscript; the plural is consistent with usage elsewhere in the Book of Mormon text that refers to the Lord visiting his people in anger; the plural usage is also supported by the ancient Greek translation of the Hebrew for Exodus 20:5 as well as by other Book of Mormon passages that prefer the plural iniquities when quoting biblical passages.