Since Job insisted he was innocent, wearing sackcloth showed grief, not asking God to forgive him. He might have worn it to show he would never take it off because no one could comfort him (Genesis 37:34–35).
I have buried my horn in the dust: A horn symbolized dignity and power (1 Samuel 2:1; Psalms 75:4–5; 89:17, 24; 92:10; 112:9; 148:14). Cutting it off caused deep humiliation (Psalm 75:10; Jeremiah 48:25; Zechariah 1:12).