Sealed book of Mormon Ch.33

AND it came to pass that there arose a people
from one of the sons of Joktan, who was a direct
descendent of Seth, the son of Adam, through
the lineage of Noah; and the name of this son
was Ophir; yea, this son was one of the thirteen
sons of Joktan who were known throughout the
world at that time as the most righteous sons of
God that had ever lived upon the earth after the
days of the great flood in the land of Cainan.
And this same Joktan was the brother of
Peleg who was the father of Mahonjad, who
was one of the loyal friends who had come to
know Jared and his brother, from whose
record I am compiling these words and
making my abridgment.
And it came to pass that because of the
exhortation and words of the brother of Jared
unto the sons of Joktan, they all followed him,
except for Ophir, into the wilderness before their
language was corrupted by those who had
invaded and conquered the great city of Babel.
And now, it hath been whispered to me by
the Spirit that an error that is written upon the
plates of brass shall be the cause of some
contention and misunderstanding among the
children of men, especially among those who
believe that they are learned, having learned
all that they know from their study of the
histories of the children of men that they have
among them.
And I have explained unto you that these
histories are many times incorrect and bias
towards the truth depending upon him who
writeth this history. And many of them are
incomplete and do not give a full account of the
history of the people.