4 Nephi 1:39

And it was because of the wickedness and abominations of their fathers, even as it was in the beginning. And they were taught to hate the children of God, even as the Lamanites were taught to hate the children of Nephi, from the beginning.

It was because of their fathers’ wickedness and terrible sins. This was just like in the beginning. They were taught to hate God’s children. This was just like the Lamanites were taught to hate Nephi’s children from the beginning.

It came from their ancestors’ wickedness and abominations, repeating old patterns. They were taught to hate God’s people, just as the ancient Lamanites had been taught to hate Nephi’s descendants.