Alma 46

Mormon takes the opportunity to teach an important principle writing -

"...whosoever will maintain this title upon the land, let them come forth in the strength of the Lord, and enter into a covenant that they will maintain their rights, and their religion, that the Lord God may bless them.
21 And it came to pass that when Moroni had proclaimed these words, behold, the people came running together with their armor girded about their loins, rending their garments in token, or as a covenant, that they would not forsake the Lord their God; or, in other words, if they should transgress the commandments of God, or fall into transgression, and be ashamed to take upon them the name of Christ, the Lord should rend them even as they had rent their garments."  (Alma 46:20–21)

The emphasis is the the people rent their garments as a "token" or "covenant" to keep the commandments which consequence that failure to do so, the Lord would rend them.  We see this in the temples today.