This has been reflected even in subsequent General Conferences. A search for the term "tender mercies" in all General Conference addresses dating back to 1970 yields hits in 18 talks. Eleven of those talks--including a few from more senior members of the Twelve--were given after Elder Bednar's. (Granted, one was another by Elder Bednar himself, but still...)
[Side note: Most Saints probably think this phrase originated with Nephi, in the Book of Mormon's introductory chapter. As I just discovered, however, the phrase also appears ten times in the Old Testament--once in Proverbs, the rest in the Book of Psalms.]
In the years to follow, I predict, usage of this phrase in General Conference and among the Saints in general will wane somewhat; although it's a bit of an apples-to-oranges comparison, we don't hear the phrase "lengthen your stride" nearly as much as we did a generation ago.
A similar phenomenon, I suggest, is also seen in the Book of Mormon. In hopes of finding more examples of words or expressions unique to one Book of Mormon figure, the phrase 'the bands of death' caught my eye. While not exclusive to one speaker, it is nearly exclusive to a certain timeframe in Book of Mormon history. As with Elder Bednar, I believe this illustrates how the vocabulary of one servant of God is often especially influential in those of his contemporaries (or near-contemporaries).
Here are the speakers of this phrase, and the frequency with which each speaker used it:
Abinadi- 5 times (Mosiah 15:8, 9, 20, 23; 16:7)
Alma the Younger- 4 times (Alma 5:7, 9, 10; 7:12)
Amulek- twice (Alma 11:41, 42) [In the latter verse, Amulek references "the bands of this temporal death." Close enough?]
Mormon?- twice (Alma 4:14, 22:14)
‘The bands of death’ is an expression that apparently originated with Abinadi, as we have no record of any prophet, Biblical or Nephite, using it prior. Regarding Alma the Younger’s usage of it, it seems very logical he would echo language of Abinadi’s; while he was not a contemporary of Abinadi, his father, Alma the Elder, was. In fact, Abinadi was inarguably the greatest spiritual influence in Alma the Elder's life. Alma the Elder, in turn, was the greatest spiritual influence in the life of his son. Furthermore, the first thing Alma the Elder did in exile after abandoning his fraternity of false priests was record Abinadi's discourse (see Mosiah 17:4). If Alma the Younger truly "always remembered the captivity of [his] fathers" (Alma 29:12, see also Alma 29:11; 36:2, 29), he had to have had great familiarity with that discourse; it was the teachings and prophesying of Abinadi that set events in motion leading to the end of both the temporal and spiritual captivity of Alma the Elder and his followers (see Alma 5:3-13).
(By the way, to any heavy metal fans who googled 'bands of death' and ended up here... sorry.)
Alma the Younger was, himself, Amulek's chief spiritual guide, so one would almost expect to find this phrase in Amulek's vocabulary as well (with a little variation, as already pointed out). Mormon’s usage of the phrase, however, is somewhat problematic for my hypothesis, as he used it in chronicling the era of Abinadi and Alma the Younger hundreds of years after the fact. Interestingly, after Alma 22, Mormon himself never uses this phrase again when acting as narrator. This is not the sole instance where Mormon mirrors the language of his subjects exclusively in the portion of his record in which they appear. I'll delve a little more deeply into that in a later post.
Additionally, it may be incorrect to identify Mormon as the speaker in the case of Alma 22:14. To what extent he was quoting Aaron while summarizing his teachings is unclear. Unfortunately, identifying Aaron as the speaker presents its own set of problems, as it is doubtful he would have been echoing Alma the Younger. If I have my timeline right, Aaron wasn't around for the discourses found in Alma 5 and 7, as they were given during his ministry among the Lamanites. He probably had no opportunity even to read it during that time; as far as we know, he and his brothers received no communication from the Nephites during their mission.
It seems more likely that Aaron, like Alma, was echoing Abinadi, if anyone. It is reasonable to assume that all the sons of Mosiah revered Abinadi as a prophet and martyr, though his influence in their lives wasn't as significant as it was in Alma's; the immediate "fathers" of the sons of Mosiah were never in captivity as were Alma's. The fact that Aaron only uses this phrase once--again, if he does at all--would be reflective of this. (On the other hand, Aaron occupies much less of the Book of Mormon narrative to begin with, perhaps that's the only reason he uses it less.)
Even with these exceptions, I believe this to be but one example of how the language of one servant of God can influence another’s, reflecting the much more important influence of one’s commitment to Christ upon another’s. This isn’t limited just to prophets and other special witnesses of Christ, either. Choose your words carefully, then. You never know whom they'll impact.