Nephi is quoting Isaiah 29:3 which reads, I will camp against thee round about, and will lay siege against thee with a mount, and I will raise forts against thee. Without Nephi's help it would be difficult to determine that this passage had reference to the persecutions that the native American Indians suffered at the hands of the Gentiles. Nephi is going to make frequent references to Isaiah 29 and also his vision. He saw the same persecutions as referenced in 1 Nephi 13:31.