“He That is Filthy Shall Be Filthy Still”
Joseph F. McConkie, Robert L. Millet
This is a specific reference to the sons of perdition (see 2 Nephi 9:16; D&C 88:35, 102; Commentary 1:244-45).
Doctrinal Commentary on the Book of Mormon, Vol. 4
References
Mormon 9:12–14