Helaman 12
This is written through the perspective of Mormon. All the things that he says of how the Lord may say something and it shall be done come from the perspective of one who has seen this happen among his people. That is why all the things the Lord can say to man are about being cursed etc. Mormon was not happy while writing this and recording how the Nephites had previously fallen into error such that they might have been destroyed had they not repented. He knows how similar that history was to his own time when they were destroyed.