Alma 37:16 - 37:20
Alma 37: 16 But if ye keep the commandments of God, and do with these things which are sacred according to that which the Lord doth command you, (for you must appeal unto the Lord for all things whatsoever ye must do with them) behold, no power of earth or hell can take them from you, for God is powerful to the fulfilling of all his words.
Alma tells Helaman that he must be very careful on how he manages the plates. Care for them exactly as the Lord commands him. If he does so, there is no power on earth or in hell that will get them from him. Alma pleads that he will consult with the Lord whenever he wants to make changes on the plates.
Alma 37: 17 For he will fulfil all his promises which he shall make unto you, for he has fulfilled his promises which he has made unto our fathers.
This promise in relation to the plates, the Lord will make apply for Helaman as He has in the past with others who have had been responsible for their maintenance and editing.
Alma 37: 18 For he promised unto them that he would preserve these things for a wise purpose in him, that he might show forth his power unto future generations.
The Lord promised that He would do so as He wants these plates preserved for future generations so He can show His power to save.
Alma 37: 19 And now behold, one purpose hath he fulfilled, even to the restoration of many thousands of the Lamanites to the knowledge of the truth; and he hath shown forth his power in them, and he will also still show forth his power in them unto future generations; therefore they shall be preserved.
The Lord has shown that is possible by the conversion of thousands of Lamanites in the pass few years. These conversions is an example of what He means by showing his power with the written word. Again this will happen at some point in the future.
Alma 37: 20 Therefore I command you, my son Helaman, that ye be diligent in fulfilling all my words, and that ye be diligent in keeping the commandments of God as they are written.
So Alma reiterates again, that Helaman must carry out his instructions very meticulously. If he does so he will be fulfilling the Lord’s wishes.