Here’s an interesting passage from Mosiah 18:9, suggesting, on its face, that mourning with those who mourn is a Christian duty (which I believe):
9 Yea, and are willing to mourn with those that mourn; yea, and comfort those that stand in need of comfort, and to stand as witnesses of God at all times and in all things, and in all places that ye may be in, even until death, that ye may be redeemed of God, and be numbered with those of the first resurrection, that ye may have eternal life–(emphasis added)
A similar phrase appears in Matthew 5:4: “Blessed are they that mourn, for they shall be comforted.” At first glance, Alma’s speech seems to echo the Sermon on the Mount, literally multiplying that beatitude times two. But Mosiah 18:9 may have a closer cousin found in a touching and amusing passage from chapter 20 of The Adventures of Huckleberry Finn:
Then the preacher begun to preach, and begun in earnest, too; and went weaving first to one side of the platform and then the other, and then a-leaning down over the front of it, with his arms and his body going all the time, and shouting his words out with all his might; and every now and then he would hold up his Bible and spread it open, and kind of pass it around this way and that, shouting, “It’s the brazen serpent in the wilderness! Look upon it and live!” And people would shout out, “Glory! — A-a-MEN!” And so he went on, and the people groaning and crying and saying amen:
“Oh, come to the mourners’ bench! come, black with sin! (AMEN!) come, sick and sore! (AMEN!) come, lame and halt and blind! (AMEN!) come, pore and needy, sunk in shame! (A-A-MEN!) come, all that’s worn and soiled and suffering! — come with a broken spirit! come with a contrite heart! come in your rags and sin and dirt! the waters that cleanse is free, the door of heaven stands open — oh, enter in and be at rest!” (A-A-MEN! GLORY, GLORY HALLELUJAH!) (emphasis added)
What’s a “Mourner’s bench”? Could it have anything to do with Alma’s sermon?
Apparently the first documented appearance of the mourner’s bench was in 1741 when the American minister Eleazar Wheelock started targeting “sinners” by having them sit in the front bench as he gave fiery, anxiety-inducing sermons reminiscent of those of his contemporary, Jonathan Edwards. I’m not clear how Wheelock targeted the sinners under his care and got them to sit on the bench during the sermon–perhaps the executive secretary called them during the week before the Sunday service. In any event, this bench became known as the “mourner’s bench” or the “anxious seat.” The term “mourner” was used to refer to the sinner convicted of his sins under the Holy Spirit’s influence, the term “anxious” to her state of mind and lost condition. The call to come forward became known as the “altar call.” Not only would the anxious answer the call, but already saved Christians would frequently go to the mourner’s bench to mourn with those who mourned.
It wasn’t until the Second Great Awakening that the mourner’s bench took hold and became part and parcel of the revival experience, as well as ordinary church services for some congregations. Revivalist Charles Finney eventually perfected Wheelock’s system and used it along with other revival practices he called his “New Measures” to scorch western New York during the 1820s and 1830s and thereby create what Witney Cross called the Burned-Over District, Joseph Smith’s backyard and context for his First Vision.
Such an approach to Alma’s sermon in Mosiah 18:9 suggests that at a minimum, early Latter-day Saints may have interpreted this passage in the context of an altar call to the unconverted and a declaration that the converted have an obligation to assist them.
But even if early readers of the Book of Mormon may have read this and other Book of Mormon passages as favorable to revival preaching and conversion practices, it is clear that at least as early as the Nauvoo period and thereafter Latter-day Saints rejected such revival practices. John Taylor and Orson Pratt and others specifically criticized in public discourse and newspapers the use of the mourner’s bench and other revival practices among the Methodists on several occasions.
What do you think? What does “mourning with those that mourn” mean in Mosiah 18:9?
 His book by the same name is my main source for the 19th Century evangelical information here.
 See, for instance, William McLellin’s apparent use of some of Charles Finney’s “New Measures” in his Mormon preaching as reported in The Journals of William E. McLellin, p. 148 and 161 n. 53. Altar calls also often had baptismal contexts similar to Mosiah 18, as noted in the Huck Finn passage quoted above.
 See, for instance T&S 4: 341-42; and JD 13:16; 14:176; and 22:307.