Job 2:12

And when they lifted up their eyes afar off and knew him not, did not recognize their friend in this formless mass of diseased flesh, they lifted up their voice and wept, in sympathy over their friend's suffering; and they rent everyone his mantle and sprinkled dust upon their heads toward heaven, that is, they threw up handfuls of dust as high as possible to signify that the misery of Job cried to heaven, and then let it fall back on their heads to show the depth of their grief.