Rhetorical: Mormon understands that his base text is understood by his audience past the direct allusions. They understand as well the rest of the verses that are part of that sermon. Therefore, he makes a rather remarkable and startling reference. He declares that “it is given unto you to judge.” This is remarkable because his audience would remember that during the Lord’s sermon he stated:
3 Nephi 14:1
1 And now it came to pass that when Jesus had spoken these words he turned again to the multitude, and did open his mouth unto them again, saying: Verily, verily, I say unto you, Judge not, that ye be not judged. (italics added)
Mormon would appear to his audience to be directly contradicting the Savior! Mormon would have done this intentionally to heighten the attention of his audience. By making such a bold statement that appears contrary to expectations, he would have the audience paying even greater attention to the way that he would resolve this seeming contradiction.
Of course, Mormon is not contradicting what the Savior intended, only the form in which the intention was phrased. In the Bountiful redaction, as well as in the New Testament Sermon on the Mount, this statement that we should not judge is followed by a qualifying statement:
3 Nephi 14:2
2 For with what judgment ye judge, ye shall be judged; and with what measure ye mete, it shall be measured to you again.
The intent is not that we should never judge, but that we understand that when we do judge, our measuring stick will be turned upon our own performance during the final judgment. It is for this reason that Mormon turns his alteration of the phrase from the negative proscription to positive prescription.