In Mosiah 12:19-20 we find the following:
And they [the priests of Noah] began to question him [Abinadi], that they might cross him, that thereby they might have wherewith to accuse him; but he answered them boldly, and withstood all their questions, yea, to their astonishment; for he did withstand them in all their questions, and did confound them in all their words.
And it came to pass that one of them said unto him: What meaneth the words which are written, and which have been taught by our fathers, saying:
How beautiful upon the mountains are the feet of him that bringeth good tidings …
According to Dana Pike, it is interesting to ask why this is the only question from the priests to Abinadi that is preserved for us. We are told that the apparently much questioning by the priests of Noah took place before they asked Abinadi the question regarding Isaiah 52:7-10. While it is not possible to discern which record keeper had the most effect on the story (Alma1 (Mosiah 16:4), Alma2 and Mormon2 all could have influenced the content), it seems to Pike that the singular reason for the decision to include this episode in our Book of Mormon is Abinadi’s powerful teaching of the Savior, which the Nephite prophet delivered and then sealed his testimony with his life. All other questions and considerations regarding this pericope on Abinadi must be considered with this perspective in mind. [Dana M. Pike, “How Beautiful upon the Mountains”: The Imagery of Isaiah 52:7-10 and Its Occurrences in the Book of Mormon,“ in Isaiah in the Book of Mormon, pp. 289-290]
“How Beautiful Are the Feet”
Dana Pike notes that a fascinating feature of Isaiah’s use of imagery here is that not only does he mention a messenger or herald, but he also focuses on the messenger’s feet with the notation that they are ”beautiful." Feet are not generally considered among the more attractive body parts; they are functional, yes, but not beautiful. What did Isaiah intend by this description?
Interestingly, the word rendered “beautiful” in verse 7 is the Hebrew term na’ wu the word from which Joseph Smith coined the city name “Nauvoo.”
As far as “beautiful” feet are concerned, Pike proposes that it might not be the condition of the feet but their observable activity, their progress, that is being emphasized by the description “beautiful.” … thus the emphasis in this passage is on the feet of the messenger because the focus of the passage is on the delivery of the message as well as on the arrival of the messenger.
On the other hand, Pike notes a communication from Larry Dahl to effect that perhaps the feet are described as beautiful because they are clean. He observes that some of the scriptural passages that mention feet refer to the washing or cleansing of feet, symbolizing forgiveness of sins and acceptance by the Lord that can only come through the true gospel (see, for example, Exodus 30:17-21; D&C 88:74-75). Thus, in his view, the gospel is the message and the feet of the messenger(s) are clean because he/they represent the Lord. Those who accept the message share in the hope of becoming clean through Christ.
[Dana M. Pike, “How Beautiful upon the Mountains”: The Imagery of Isaiah 52:7-10 and Its Occurrences in the Book of Mormon," in Isaiah in the Book of Mormon, pp. 258, 288]