יונה, פרק ג׳, פסוק ו׳

The warning of approaching destruction brings about a dramatic shift in the city's highest leadership. The supreme ruler demonstrates complete submission, willingly stripping away every symbol of his power. Chronologically, the news of the prophet's warning reaches the king, and his reaction occurs, before the general public begins their mass wearing of sackcloth [אבן עזרא]. As the report of the impending doom reaches his ears [רד״ק, מצודת דוד], it moves the king to humble himself personally [מלבי״ם].

He achieves this through a gradual process of lowering his own dignity and honor [חומת אנך]. First, he abandons his royal throne to sit upon the ground [מצודת דוד]. Next, he removes his magnificent royal robe, an expensive garment representing his wealth and glory [רש״י, רד״ק, מצודת ציון, ביאור שטיינזלץ, אבן עזרא]. In place of his majestic clothing, he covers his flesh [אבן עזרא] with a thick, coarse sackcloth [מצודת ציון]. Rather than resting on his seat of power, he chooses to sit directly in ashes [מלבי״ם]. These actions of wearing rough fabric and sitting in ashes are clear signs of deep mourning [ביאור שטיינזלץ]. By adopting them, the king acts as though his great city has already been completely overthrown and destroyed [אברבנאל].