Isaiah 9:3 thou hast multiplied the nation
and not increased the joy
2 Nephi 19:3 thou hast multiplied the nation
and increased the joy
The Masoretic scribes interpreted the
original Hebrew לא /lo’/ ‘not’ in this line as an error for לו /lō/ ‘for him’.
Modern translations of Isaiah [9]:3, such as the Revised Standard Version, read
“thou hast multiplied the nations // thou hast increased its joy”,
without any negative and with its representing the conjectured ‘for him’.
The Book of Mormon reading, where the not has been omitted, may simply
represent its own conjectural emendation since the rest of the verse consistently
refers to the joy of the people in a positive way: “they joy before the according
to the joy in the harvest and as men rejoice when they divide the spoil”. (Royal
Skousen, The History of the Text of the Book of Mormon, Part 5: The King James
Quotations in the Book of Mormon [Provo, Utah: Foundation for Ancient Research
and Mormon Studies; Brigham Young University Studies, 2019, 148)