While again there are two insignificant words added by the King James translators (vv. 19, 22), the punctuation difference between the Book of Mormon and the King James texts (v. 19) needs to be commented upon. As punctuated, the King James text asks two questions at the end of verse 19. The second question is not a complete sentence. It is the same question asked in the Book of Mormon text. The question was an answer given by those who were told not to seek revelation from sources of witchcraft. Their answer was an attempt to justify their actions.
When people request and receive revelation from sources not of God, these sources are to be tested according to the law (of Moses) and the testimony (of the prophets). The Prophet Joseph Smith used the same phrase, “to the law and to the testimony” (v. 20) in reference to testing the principles he was teaching. Joseph said, “these principles are poured out all over the scriptures” (TPJS, 373–374).
Isaiah saw into the future of both houses of Israel. He saw that both houses would fall into captivity and darkness ( apostasy) (vv. 21–22). The following verses are the basis of this interpretation.