Make thee bald. — Joel appeals to the land of Judah to go into deep mourning by reason of the loss of her children, slain in war or carried into captivity. The shaving of the head as a token of grief was common amongst Eastern nations, and is distinct from the idolatrous custom of cutting the hair in a peculiar shape denounced by Jeremiah (Jeremiah 9:26, margin), and forbidden by the Jewish Law (Leviticus 19:27-28).
As the eagle. — The Hebrew name for eagle includes the different kinds of vultures. Entire baldness is a marked feature of the vulture.
The terms in which Joel speaks of the entire desolation of the cities of Judah must refer to a more complete calamity than that inflicted by Sennacherib; they rather suit the period of the Babylonian captivity.