And there came a messenger, and told him, saying, They have brought the heads of the king’s sons. And he said, Lay ye them in two heaps at the entering in of the gate until the morning. (2 Kings 10:8)
Heads of those executed are frequently placed on public exhibit in Eastern countries even today. Assyrian sculptures often show heaps of heads at the gates of cities. The object of such practices was, of course, to strike terror into the hearts of any who might think to resist.