'Head Covered' in the Bible

And David went up by the ascent of mount Olivet, and wept as he went up, and had his head covered, and he went barefoot: and all the people that was with him covered every man his head, and they went up, weeping as they went up.

And Mordecai came again to the king's gate. But Haman hasted to his house mourning, and having his head covered.