Sackcloth and ashes are materials associated with repentance and prayer. The speaker said, “except they repent in sackcloth and ashes, and cry mightily to the Lord their God,” he would not hear their prayers or deliver them from afflictions (Mosiah 11:25).
Nephi saw that the people “had repented and did humble themselves in sackcloth,” and he cried again unto the Lord (Helaman 11:9). The speaker declared, “I make sackcloth their covering,” and a “girding of sackcloth” is named in place of a stomacher (2 Nephi 7:3; 2 Nephi 13:24).