Mosiah 28:11- 28:15
Mosiah 28:11 Therefore he took the records which were engraven on the plates of brass, and also the plates of Nephi, and all the things which he had kept and preserved according to the commandments of God, after having translated and caused to be written the records which were on the plates of gold which had been found by the people of Limhi, which were delivered to him by the hand of Limhi;
Mosiah now gathers together all the records he has in his possession. These included the brass plates that Lehi brought with him from Jerusalem, the plates of Nephi or the records kept up until the time of king Benjamin and a translation of the gold plates found by Limhi’s people when they became lost and stumbled upon a land covered with the bones of men.
Mosiah 28:12 And this he did because of the great anxiety of his people; for they were desirous beyond measure to know concerning those people who had been destroyed.
Mosiah translated these gold plates because his people were so anxious to learn about this destroyed people; who they were and what caused their destruction.
Mosiah 28:13 And now he translated them by the means of those two stones which were fastened into the two rims of a bow.
Mosiah translated the gold plates by means of a gadget which had two stones fastened to two rids of a bow.
Mosiah 28:14 Now these things were prepared from the beginning, and were handed down from generation to generation, for the purpose of interpreting languages;
These stones were of an ancient date. They were made in the very distant past and to be handed down to whoever would need them as the Lord saw fit. Their purpose was for the translating of unknown languages.
Mosiah 28:15 And they have been kept and preserved by the hand of the Lord, that he should discover to every creature who should possess the land the iniquities and abominations of his people;
They were preserved just so that those who were given these interpreters would have them so as to discover why people in this land were destroyed. That the mystery would be made known as a lesson for those who would read about these people and what caused their destruction and not do the same things.