Alma 53:3–5

And it came to pass that after the Lamanites had finished burying their dead and also the dead of the Nephites, they were marched back into the land Bountiful; and Teancum, by the orders of Moroni, caused that they should commence laboring in digging a ditch round about the land, or the city, Bountiful.

And he caused that they should build a breastwork of timbers upon the inner bank of the ditch; and they cast up dirt out of the ditch against the breastwork of timbers; and thus they did cause the Lamanites to labor until they had encircled the city of Bountiful round about with a strong wall of timbers and earth, to an exceeding height.

And this city became an exceeding stronghold ever after; and in this city they did guard the prisoners of the Lamanites; yea, even within a wall which they had caused them to build with their own hands. Now Moroni was compelled to cause the Lamanites to labor, because it was easy to guard them while at their labor; and he desired all his forces when he should make an attack upon the Lamanites.

From section: Bountiful Fortifications

From page: Moroni and Teancum on the Eastern Front