Jarom

The internal message of Jarom to his people and readers of his record that live upon this land is that there is a direct relationship between repentance, righteousness and prosperity and wickedness and being swept away. In that -

"...it is expedient that much should be done among this people, because of the hardness of their hearts, and the deafness of their ears, and the blindness of their minds, and the stiffness of their necks; nevertheless, God is exceedingly merciful unto them, and has not as yet swept them off from the face of the land." (Book of Mormon | Jarom 1:3)

Even such the Lamanites -

"...came many times against us, the Nephites, to battle. But our kings and our leaders were mighty men in the faith of the Lord; and they taught the people the ways of the Lord; wherefore, we withstood the Lamanites and swept them away out of our lands, and began to fortify our cities, or whatsoever place of our inheritance." (Book of Mormon | Jarom 1:7)

And thus -

"...the word of the Lord was verified, which he spake unto our fathers, saying that: Inasmuch as ye will keep my commandments ye shall prosper in the land.
10 And it came to pass that the prophets of the Lord did threaten the people of Nephi, according to the word of God, that if they did not keep the commandments, but should fall into transgression, they should be destroyed from off the face of the land." (Book of Mormon | Jarom 1:9 - 10)

For -

"...the prophets, and the priests, and the teachers, did labor diligently, exhorting with all long-suffering the people to diligence; teaching the law of Moses, and the intent for which it was given; persuading them to look forward unto the Messiah, and believe in him to come as though he already was. And after this manner did they teach them.
12 And it came to pass that by so doing they kept them from being destroyed upon the face of the land; for they did prick their hearts with the word, continually stirring them up unto repentance." (Book of Mormon | Jarom 1:11 - 12)

It always seemed to hanging over the Nephites heads that if they did what was right, they would prosper. And if they failed to do so and refused to repent, the promise was that they would be swept off the land.