Mormon paraphrases Nephi about the "great and last day"

In Helaman 12 we get an entire chapter of editorial lamentation by Mormon about the frailties of humanity.  He ends his lament with these words:

25 And I would that all men might be saved. But we read that in the great and last day there are some who shall be cast out, yea, who shall be cast off from the presence of the Lord;

And just where do \”we read\” these words? This is a pretty clear reference to the final words of Nephi, found in 2 Nephi 33:

12 And I pray the Father in the name of Christ that many of us, if not all, may be saved in his kingdom at that great and last day.
…
14 And you that will not partake of the goodness of God, and respect the words of the Jews, and also my words, and the words which shall proceed forth out of the mouth of the Lamb of God, behold, I bid you an everlasting farewell, for these words shall condemn you at the last day.