Not only have the Nephites multiplied but they have become exceedingly rich in precious metals and precious things, probably referring to jewels. They had also become great artisans in working with wood, in constructing great buildings and manufacturing certain kinds of machinery. How we wish we could discover just what this word really means. Did these ancients stumble onto the secret of power tools and power equipment?
Jarom says they became expert in working iron, copper and brass and steel. He also says they made tools of every kind for agriculture and also manufactured weapons of war. Someday, we may discover that this verse contains a hint of the manner in which the ancient inhabitants of America cut and transported over great distances the giant monolithic stones sometimes weighing over 100 tons, which were used in many places in South America. In Jarom's generation the Nephites verified the literal reality of God's promises that if they would obey his commandments they would prosper in the land.
Jarom frankly states that the prophets of the Lord had to actually threaten the people and vigorously warn them of the consequences of their ignoring the Lord's declaration wherein he had told them that if they fell into transgression they would be destroyed as a people.