'Sackcloth' in the Bible

It shall happen that instead of sweet spices, there shall be rottenness; instead of a belt, a rope; instead of well set hair, baldness; instead of a robe, a wearing of sackcloth; and branding instead of beauty.

In their streets, they clothe themselves in sackcloth. In their streets and on their housetops, everyone wails, weeping abundantly.

at that time Yahweh spoke by Isaiah the son of Amoz, saying, "Go, and loosen the sackcloth from off your waist, and take your shoes from off your feet." He did so, walking naked and barefoot.

In that day, the Lord, Yahweh of Armies, called to weeping, and to mourning, and to baldness, and to dressing in sackcloth:

Tremble, you women who are at ease! Be troubled, you careless ones! Strip yourselves, make yourselves naked, and put sackcloth on your waist.

It happened, when king Hezekiah heard it, that he tore his clothes, covered himself with sackcloth, and went into Yahweh's house.

He sent Eliakim, who was over the household, and Shebna the scribe, and the elders of the priests, covered with sackcloth, to Isaiah the prophet, the son of Amoz.

I clothe the heavens with blackness, and I make sackcloth their covering."

Is such the fast that I have chosen? the day for a man to afflict his soul? Is it to bow down his head as a rush, and to spread sackcloth and ashes under him? Will you call this a fast, and an acceptable day to Yahweh?