Leitwort is the intentional use of a word, over and over again to highlight a theme within a text. The story of Jonah is a good example of its use:

3 But Jonah rose up to flee unto Tarshish from the presence of the Lord, and went down to Joppa; and he found a ship going to Tarshish: so he paid the fare thereof, and went down into it, to go with them unto Tarshish from the presence of the Lord.
4 But the Lord sent out a great wind into the sea, and there was a mighty tempest in the sea, so that the ship was like to be broken.
5 Then the mariners were afraid, and cried every man unto his god, and cast forth the wares that were in the ship into the sea, to lighten it of them. But Jonah was gone down into the sides of the ship; and he lay, and was fast asleep. (Jonah 1)

2 And said, I cried by reason of mine affliction unto the Lord, and he heard me; out of the belly of hell cried I, and thou heardest my voice.
6 I went down to the bottoms of the mountain (Jonah 2)

Here is an example from The Book of Mormon:

6 Behold, my sons, I desire that ye should remember to keep the commandments of God; and I would that ye should declare unto the people these words. Behold, I have given unto you the names of our first parents who came out of the land of Jerusalem; and this I have done that when you remember your names ye may remember them; and when ye remember them ye may remember their works; and when ye remember their works ye may know how that it is said, and also written, that they were good.
7 Therefore, my sons, I would that ye should do that which is good, that it may be said of you, and also written, even as it has been said and written of them.
8 And now my sons, behold I have somewhat more to desire of you, which desire is, that ye may not do these things that ye may boast, but that ye may do these things to lay up for yourselves a treasure in heaven, yea, which is eternal, and which fadeth not away; yea, that ye may have that precious gift of eternal life, which we have reason to suppose hath been given to our fathers.
9 O remember, remember, my sons, the words which king Benjamin spake unto his people; yea, remember that there is no other way nor means whereby man can be saved, only through the atoning blood of Jesus Christ, who shall come; yea, remember that he cometh to redeem the world.
10 And remember also the words which Amulek spake unto Zeezrom, in the city of Ammonihah; for he said unto him that the Lord surely should come to redeem his people, but that he should not come to redeem them in their sins, but to redeem them from their sins.
11 And he hath power given unto him from the Father to redeem them from their sins because of repentance; therefore he hath sent his angels to declare the tidings of the conditions of repentance, which bringeth unto the power of the Redeemer, unto the salvation of their souls.
12 And now, my sons, remember, remember that it is upon the rock of our Redeemer, who is Christ, the Son of God, that ye must build your foundation; that when the devil shall send forth his mighty winds, yea, his shafts in the whirlwind, yea, when all his hail and his mighty storm shall beat upon you, it shall have no power over you to drag you down to the gulf of misery and endless wo, because of the rock upon which ye are built, which is a sure foundation, a foundation whereon if men build they cannot fall. (Helaman 5)