Joshua 8:18

"And Jehovah said unto Joshua, Stretch out the javelin that is in thy hand toward Ai; for I will give it into thy hand. And Joshua stretched out the javelin that was in his hand toward the city. And the ambush rose quickly out of their place, and they ran as soon as he had stretched out his hand, and entered the city, and took it; and they hasted and set the city on fire. And when the men of Ai looked behind them, they saw, and, behold, the smoke of the city ascended up to heaven, and they had no power to flee this way or that way: and the people that fled to the wilderness turned back upon their pursuers. And when Joshua and all Israel saw that the ambush had taken the city, and that the smoke of the city ascended, then they turned again, and slew the men of Ai. And the others came forth out of the city against them; so they were in the midst of Israel, some on this side, and some on that side: and they smote them, so that they let none of them remain or escape. And the king of Ai they took alive, and brought him to Joshua."

"Stretch out the javelin ..." Holmes made fun of this outstretched javelin as a signal, saying, "It looks like a piece of sympathetic magic."[19] However, totally aside from any miraculous power which might have been released by the Divine command for Joshua to stretch out the javelin, there is the definite possibility that from a strategic elevation (the area was full of such places), the spear with which Joshua signaled the attack, "probably had a flag or streamer on it to make it more easily visible from the heights where he stood."[20] Another possibility was mentioned by Blair: "Joshua probably gave the signal by reflecting the sun from the wide flat blade of his spear."[21]

"So they let none of them remain or escape ..." The literal words here in the Hebrew are: "Until there remained to them neither remainder nor fugitive."[22] The extent of the slaughter in the conquest of Canaan must have been one of the most terrible disasters of all history. Israel systematically butchered entire populations of every city that they took.