Alma 37:21 - 37:25

Alma 37: 21 And now, I will speak unto you concerning those twenty-four plates, that ye keep them, that the mysteries and the works of darkness, and their secret works, or the secret works of those people who have been destroyed, may be made manifest unto this people; yea, all their murders, and robbings, and their plunderings, and all their wickedness and abominations, may be made manifest unto this people; yea, and that ye preserve these interpreters.

25 I will bring forth out of darkness unto light all their secret works and their abominations; and except they repent I will destroy them from off the face of the earth; and I will bring to light all their secrets and abominations, unto every nation that shall hereafter possess the land.

Alma 37: 22 For behold, the Lord saw that his people began to work in darkness, yea, work secret murders and abominations; therefore the Lord said, if they did not repent they should be destroyed from off the face of the earth.

The Lord had warned these people that their evil works would lead to their complete destruction if they did not repent.

Alma 37: 23 And the Lord said: I will prepare unto my servant Gazelem, a stone, which shall shine forth in darkness unto light, that I may discover unto my people who serve me, that I may discover unto them the works of their brethren, yea, their secret works, their works of darkness, and their wickedness and abominations.

The interpreters were created to show the evil acts of the people into those who had possession of the interpreters. They were originally give to Gazelem.

We do not know who this person is other than he was a Jaredite.

Alma 37: 24 And now, my son, these interpreters were prepared that the word of God might be fulfilled, which he spake, saying:

The creation of the interpreters were a fulfillment of prophecy.

Alma 37: 25 I will bring forth out of darkness unto light all their secret works and their abominations; and except they repent I will destroy them from off the face of the earth; and I will bring to light all their secrets and abominations, unto every nation that shall hereafter possess the land.

Their purpose was to reveal to all nations and peoples the evil acts of all those who live on the promise land.