This specific expression conveys an enduring theme of the scriptures. From the beginning, the Lord commands Adam: “Wherefore teach it unto your children, that all men, everywhere, must repent, or they can in nowise inherit the kingdom of God, for no unclean thing can dwell there, or dwell in his presence; for, in the language of Adam, Man of Holiness is his name, and the name of his Only Begotten is the Son of Man, even Jesus Christ, a righteous Judge, who shall come in the meridian of time” (Moses 6:57). Nephi reiterates the theme as follows: “Wherefore, if ye have sought to do wickedly in the days of your probation, then ye are found unclean before the judgment-seat of God; and no unclean thing can dwell with God; wherefore, ye must be cast off forever” (1 Nephi 10:21). Amulek reminds Zeezrom: “And I say unto you again that he cannot save them in their sins; for I cannot deny his word, and he hath said that no unclean thing can inherit the kingdom of heaven; therefore, how can ye be saved, except ye inherit the kingdom of heaven? Therefore, ye cannot be saved in your sins” (Alma 11:37). And Alma focuses on this same theme in counseling his wayward son, Corianton: “But behold, an awful death cometh upon the wicked; for they die as to things pertaining to things of righteousness; for they are unclean, and no unclean thing can inherit the kingdom of God; but they are cast out, and consigned to partake of the fruits of their labors or their works, which have been evil; and they drink the dregs of a bitter cup” (Alma 40:26). Now the resurrected Lord emphasizes once again this eternal truth, “that no unclean thing can enter into his kingdom” (3 Nephi 27:19).
These five passages are persuasive in their finality. The purpose for their being repeated consistently is to persuade men to believe in Christ, to do good (see Moroni 7:16), and to avail themselves of the power of the Redemption through faith and the cleansing process of repentance and baptism by water and fire. If we cannot enter heaven in our state of uncleanliness, then we must seek the mighty change of heart and become sanctified in order to return home to the presence of God.