I have to admit that I am pretty weak when it comes to the Hebrew Bible. But my perception is that the divine sword of the Lord is wielded by angels, typically in vision, to show God’s displeasure with the principles of the narrative in which they appear.
In 1 Chronicles 21, we have David, who decides to execute a census of Israel in spite of God’s command. The Lord speaks to David’s seer, Gad, and gives David a choice between destruction by famine or by army. David chooses famine and the Lord sends the Destroyer to move upon Israel:
15 And God sent an angel unto Jerusalem to destroy it: and as he was destroying, the Lord beheld, and he repented him of the evil, and said to the angel that destroyed, It is enough, stay now thine hand. And the angel of the Lord stood by the threshingfloor of Ornan the Jebusite.
16 And David lifted up his eyes, and saw the angel of the Lord stand between the earth and the heaven, having a drawn sword in his hand stretched out over Jerusalem. Then David and the elders of Israel, who were clothed in sackcloth, fell upon their faces.
David repents and prays to God to stay his hand and the angel responds to Gad who speaks in the name of the Lord. The instruction is that David is to go build an altar at Ornan’s place and offer sacrifice. It is a poignant narrative, really. Upon David’s sacrifice, “the Lord commanded the angel; and he put up his sword again into the sheath thereof.”
I’m looking forward to Sam’s treatment of the Destroyer (I remember his excellent MHA paper on the Word of Wisdom on this), to be more widely available. But, I think that this vignette of David was pregnant with meaning for the nascent Mormons (as an aside, the other famous sword baring angel was the one which the talking donkey evades on behalf of Balaam; also, the flaming sword east of Eden – Am I right to understand that it was a giant spinning blade of fire, which was not wielded by a personified being?). Perhaps the most famous recapitulation of this episode was Joseph Smith and his introduction of polygamy.
However, my most favorite sword baring angels in the Restoration, aren’t what I would call Destroyers. To me, they seem to be better understood as part of the heavenly host. For example, before the deadline to leave Jackson County arrived, the locals nevertheless threatened the Mormons and subjected their property to various levels of vandalism. Mary Rollins Lightner, who is best known for saving leaves of the Book of Commandments and then running into the corn field, wrote of one attack on her home in her autobiography:
One night, a great many got together and stoned our House part of which was hewed Logs, the front was Brick, after Breaking all the Windows, they commenced to tear of[f] the Roof of the Brick part, amidtst awful oaths, and howls, that were terrible to hear, all of a sudden, they left, and all was quiet. Next morning, Oliver, and John Whitmer came to the ^House^ and informed us, that hearing the terrible noise in the night, they feared for our lives and started to come to our assistance But hapening to look up to the Roof of our House they saw two Angels with drawn swords in their hands, standing on the Ridge pole, then, they retired knowing we were safe. 
The other account is from the January 21, 1836 entry of Joseph Smith’s journal. He and other Church leaders had spent the evening washing, anointing and then sealing blessings upon each other. Upon completion of this liturgy, a vision of heaven opened up to Smith. Section 137 of the Doctrine and Covenants was an extract of this vision added in 1981 in conjunction with 138. This is where he sees his parents and Alvin in the Celestial kingdom. The vision goes on and among other things, Smith saw:
Eldr Brigham Young standing in a strange land, in the far south west, in a desert place, upon a rock in the midst of about a dozen men of colour, who, appeared hostile He was preaching to them in their own toung, and the angel of God standing above his head with a drawn sword in his hand protecting him, but he did not see it 
I think all of these cases are best understood as visions. I don’t imagine that the Missourians saw the angel. I imagine Lightner would have remarked some audible reaction had they seen it. Instead, it was a vision to Cowdery and Whitmer and perhaps assured them that their cause was not completely lost (despite the dire circumstances). God was on their side.
These visions situated the Saints within the broad cosmic struggle between good and evil. This is evidenced a week after JS’s vision into heaven. After administering the Temple liturgy to a group of men, “Roger Orton saw a flaming Angel riding upon a horse of fire with a flaming sword in his hand followed by five others— encircle the house & protect the saints even the Lords anointed from the power of Satan & a host of evil spirits which were striving to disturb the saints—”
Like the biblical antecedents, Mormon angels were anthropomorphic beings. However, the Destoyer was no longer the bane of sinner, but the defender of the Saint. While this isn’t universally the case (note previous mention of JS and his polygamy commander, among several other examples), perhaps it made more sense for early Mormons to see these angels as battling with them. Instead of ontologically discrete sentinels for Yaweh, they were fellow citizens and fellow Saints, albeit temporally displaced.
- Mary Rollins Lightner, Autobiography, 6, holograph, Box 14, fd. 4, Susa Young Gates Papers, Utah Historical Society Archives, Salt Lake City.
- JS, Journal, January 21, 1836, JSPP Online, Documents, ID:6663; Journals, Vol. 1, 170-71.
- Ibid., January 28, 1836.