When the unconverted Lamanites see that their brethren would die rather than defend themselves, their hearts are “swollen” with mercy.
Alma 24:20–27
20 And it came to pass that their brethren, the Lamanites, made preparations for war, and came up to the land of Nephi for the purpose of destroying the king, and to place another in his stead, and also of destroying the people of Anti-Nephi-Lehi out of the land.
21 Now when the people saw that they were coming against them they went out to meet them, and prostrated themselves before them to the earth, and began to call on the name of the Lord; and thus they were in this attitude when the Lamanites began to fall upon them, and began to slay them with the sword.
22 And thus without meeting any resistance, they did slay a thousand and five of them; and we know that they are blessed, for they have gone to dwell with their God.
23 Now when the Lamanites saw that their brethren would not flee from the sword, neither would they turn aside to the right hand or to the left, but that they would lie down and perish, and praised God even in the very act of perishing under the sword—
24 Now when the Lamanites saw this they did forbear from slaying them; and there were many whose hearts had swollen in them for those of their brethren who had fallen under the sword, for they repented of the things which they had done.
25 And it came to pass that they threw down their weapons of war, and they would not take them again, for they were stung for the murders which they had committed; and they came down even as their brethren, relying upon the mercies of those whose arms were lifted to slay them.
26 And it came to pass that the people of God were joined that day by more than the number who had been slain; and those who had been slain were righteous people, therefore we have no reason to doubt but what they were saved.
27 And there was not a wicked man slain among them; but there were more than a thousand brought to the knowledge of the truth; thus we see that the Lord worketh in many ways to the salvation of his people.
President Ezra Taft Benson said:
“I have seen, at close range, the manner in which the Lord has turned disasters—war, occupation, and revolution—into blessings.”
(The Teachings of Ezra Taft Benson [1988], 168.)
