'Sackcloth' in the Bible

For this, gird you with sackcloth, lament and howl! for the fierce anger of Jehovah is not turned away from us.

Daughter of my people, gird thee with sackcloth, and roll thyself in ashes: make mourning, as for an only son bitter lamentation; for the spoiler cometh suddenly upon us.

For every head is bald, and every beard clipped; upon all the hands are cuttings, and upon the loins sackcloth.

Howl, Heshbon! for Ai is laid waste; cry, daughters of Rabbah, gird you with sackcloth, lament and run to and fro within the enclosures: for Malcam shall go into captivity, his priests and his princes together.