Alma 12:36
36 And now, my brethren, behold I say unto you, that if ye will harden your hearts ye shall not enter into the rest of the Lord; therefore your iniquity provoketh him that he sendeth down his wrath upon you as in the first provocation, yea, according to his word in the last provocation as well as the first, to the everlasting destruction of your souls; therefore, according to his word, unto the last death, as well as the first.
Alma 30:46
46 And now it came to pass that Alma said unto him: Behold, I am grieved because of the hardness of your heart, yea, that ye will still resist the spirit of the truth, that thy soul may be destroyed.
Alma 31:31
31 O Lord, my heart is exceedingly sorrowful; wilt thou comfort my soul in Christ. O Lord, wilt thou grant unto me that I may have strength, that I may suffer with patience these afflictions which shall come upon me, because of the iniquity of this people.
Alma 32:28
28 Now, we will compare the word unto a seed. Now, if ye give place, that a seed may be planted in your heart, behold, if it be a true seed, or a good seed, if ye do not cast it out by your unbelief, that ye will resist the Spirit of the Lord, behold, it will begin to swell within your breasts; and when you feel these swelling motions, ye will begin to say within yourselves—It must needs be that this is a good seed, or that the word is good, for it beginneth to enlarge my soul; yea, it beginneth to enlighten my understanding, yea, it beginneth to be delicious to me.
Alma 37:34
34 Teach them to never be weary of good works, but to be meek and lowly in heart; for such shall find rest to their souls.Helaman 7:8
6 Now this great iniquity had come upon the Nephites, in the space of not many years; and when Nephi saw it, his heart was swollen with sorrow within his breast; and he did exclaim in the agony of his soul:3 Nephi 17:16
17 And no tongue can speak, neither can there be written by any man, neither can the hearts of men conceive so great and marvelous things as we both saw and heard Jesus speak; and no one can conceive of the joy which filled our souls at the time we heard him pray for us unto the Father.Mormon 3:12
12 Behold, I had led them, notwithstanding their wickedness I had led them many times to battle, and had loved them, according to the love of God which was in me, with all my heart; and my soul had been poured out in prayer unto my God all the day long for them; nevertheless, it was without faith, because of the hardness of their hearts.
2 Nephi 1:21-22
21 And now that my soul might have joy in you, and that my heart might leave this world with gladness because of you, that I might not be brought down with grief and sorrow to the grave, arise from the dust, my sons, and be men, and be determined in one mind and in one heart, united in all things, that ye may not come down into captivity;
22 That ye may not be cursed with a sore cursing; and also, that ye may not incur the displeasure of a just God upon you, unto the destruction, yea, the eternal destruction of both soul and body.
Jacob 2:16
16 O that he would rid you from this iniquity and abomination. And, O that ye would listen unto the word of his commands, and let not this pride of your hearts destroy your souls!
Many of these do not seem significant. I'd like to focus on the examples which seem to be poetic.
In 2 Nephi 1 21-22, Lehi starts the phrase with a parallel usage of "heart" and "soul" to ask his sons to behave in a way that will bring him joy and gladness:
"...soul...joy...you...heart...gladness...you..."
In Helaman 7:8, Mormon sets up Nephi-2's lament about not living in an earlier age with this poetic construct:
"...heart...sorrow...agony...soul..."
Jacob 2:16 also seems to use an intentional construct:
"pride...hearts...destroy...souls"