Alma 25

 Again we read that after multiple opportunities - 

"it came to pass that when the Lamanites saw that they could not overpower the Nephites they returned again to their own land; and many of them came over to dwell in the land of Ishmael and the land of Nephi, and did join themselves to the people of God, who were the people of Anti-Nephi-Lehi.

14 And they did also bury their weapons of war, according as their brethren had, and they began to be a righteous people; and they did walk in the ways of the Lord, and did observe to keep his commandments and his statutes."  (Alma 25:13–14)

Our Father in Heaven continues to give His children opportunities to repent and change.