3 Nephi 6:12, 14

12. And the people began to be distinguished by ranks, according to their riches and their chances for learning; yea, some were ignorant because of their poverty, and others did receive great learning because of their riches. 

14. And thus there became a great inequality in all the land, insomuch that the church began to be broken up; yea, insomuch that in the thirtieth year the church was broken up in all the land save it were among a few of the Lamanites who were converted unto the true faith; and they would not depart from it, for they were firm, and steadfast, and immovable, willing with all diligence to keep the commandments of the Lord.