Storms of sand and dust sometimes overtake Eastern travellers. They are very dreadful, many perishing under them. Jehovah threatens to bring on the land of Israel, as a punishment for forsaking him, a rain of "powder and dust" (Deuteronomy 28:24).
To cast dust on the head was a sign of mourning (Joshua 7:6); and to sit in dust, of extreme affliction (Isaiah 47:1). "Dust" is used to denote the grave (Job 7:21). "To shake off the dust from one's feet" against another is to renounce all future intercourse with him (Matthew 10:14; Acts 13:51). To "lick the dust" is a sign of abject submission (Psalms 72:9); and to throw dust at one is a sign of abhorrence (2 Samuel 16:13; Compare Acts 22:23).
These dictionary topics are from M.G. Easton M.A., D.D., Illustrated Bible Dictionary, Third Edition, published by Thomas Nelson, 1897. Public Domain, copy freely.
Easton, Matthew George. "Entry for 'Dust'". "Easton's Bible Dictionary".