"The sword of the Spirit, which is the word of God" (Eph. 6:17). A sword is not armor but Paul included it because without an offensive weapon, even the most heavily armored person can fall. It is difficult to withstand attacks without being able to deliver your own, whether in offense or defense. The sword represents the Spirit and the word of God. The Lord stated in the latter-days, "Behold, I am God; give heed unto my word, which is quick and powerful, sharper than a two-edged sword, to the dividing asunder of both joints and marrow; therefore give heed unto my words" (D&C 6:2; 11:2; 12:2; 14:2). A key addendum to this verse is also found in the Doctrine and Covenants: "Open ye your ears and hearken to the voice of the Lord your God, whose word is quick and powerful, sharper than a two-edged sword, to the dividing asunder of the joints and marrow, soul and spirit; and is a discerner of the thoughts and intents of the heart" (D&C 33:1; emphasis added). Thus, the sword of the Spirit helps us discern the thoughts and intents of others. There are numerous examples of this in the Book of Mormon. One such example is Alma and Amulek. They understood and confounded Zeezrom with the Spirit and the word of God. The Savior always understood what the Pharisees and scribes were thinking; He knew their intents. This is why the Spirit is a weapon; through the Spirit we can reveal falsehoods in others and defend our testimonies against their attacks. We can expose their intents and confound them with the word of God. The truth pierces the soul and severs lies. The Spirit acts as a powerful testifying force, cutting to the heart of those with ears to hear.
Throughout the scriptures we find other "spiritual clothing." Isaiah mentioned a couple articles of clothing in chapter 61: "I will greatly rejoice in the Lord, my soul shall be joyful in my God; for he hath clothed me with the garments of salvation, he hath covered me with the robe of righteousness, as a bridegroom decketh himself with ornaments, and as a bride adorneth herself with her jewels" (Isa. 61:10; emphasis added). We should wear garments of salvation, clothing that is pure, clean, and worthy of and representative of the covenants we make with God. Latter-day accounts of Heavenly visitors often include descriptions of the visitors wearing bright white robes (e.g., JS-H 1:31). As Isaiah stated, the robes represent and reflect righteousness. Isaiah also stated that our scarlet sins can be white as snow (Isa. 1:18) through repentance and through the redeeming blood of Christ. The whiteness of the robes represents purity, holiness, and righteousness. The great Book of Mormon teacher Jacob taught about the Final Judgment: "We shall have a perfect knowledge of all our guilt, and our uncleanness, and our nakedness; and the righteous shall have a perfect knowledge of their enjoyment, and their righteousness, being clothed with purity, yea, even with the robe of righteousness" (2 Ne. 9:14).
Now returning to the Isaiah verse quoted before, I think it is significant that Isaiah compared putting on the robe to a bridegroom and bride preparing themselves for marriage. All the ornamentation that we need, all that is truly precious, is a robe of righteousness. This is especially true in context of the numerous scriptures in the Book of Mormon where the wicked were known for wearing and being so enthralled with "fine-twined linens" (see 1 Ne. 13:7-8; Alma 4:6). What is it about clothing and wickedness? It's not the clothing per se, it's the pride that people have in wearing nicer clothes than others. It's possible to be righteous and wear beautiful clothing (see Alma 1:29) just like it's possible to be righteous and wealthy. However, pride and selfishness so readily follow such blessings. It's like Tevye in the musical Fiddler on the Roof who sings "If I were a rich man." While meant to be somewhat humorous, he wants to be rich so he wouldn't have to work hard, could see his wife strutting around like a peacock putting on airs, and have others see him spend so much time with the Rabbi and other learned men. There is a difference between the humble followers of Christ putting on their robes of righteousness and garments of salvation and the worldly wicked in the great and spacious building arraying themselves as peacocks in their gaudy garments of wickedness.
I pray that we will decide to wear spiritual clothing worthy of who we are as children of God. We should protect ourselves with the armor of God and join the fight against sin.
Link to part 2 of this essay.