The _ruse_ was that the ambush should be concealed behind the city; that Ai, as before, should be attacked from the east by the main body of troops; that on receiving the onslaught from the city they should seem to be defeated as before; that Joshua, probably standing on some commanding height, should give a signal to the men in ambush by raising his spear; whereupon these men should rush down on the now deserted place and set it on fire. On seeing the flames, the pursuers would naturally turn and rush back to extinguish them; then the main body of Israel would turn likewise, and thus the enemy would be caught as in a trap from which there was no escape, and fall a victim to the two sections of Israel. To plots of this kind, the main objection in a strategical sense lies in the risk of detection. For the five thousand who went to station themselves in the west it was a somewhat perilous thing to separate themselves from the host, and place themselves in the heart of enemies both in front and in rear. It needed strong faith to expose themselves in such a situation. Suppose they had been detected as they went stealing along past Ai in the darkness of the night; suppose they had come on some house or hamlet, and wakened the people, so that the alarm should have been carried to Ai, what would have been the result? It was well for Israel that no such mishap occurred, and that they were able in silence to reach a place where they might lie concealed. The ground is so broken by rocks and ravines that this would not have been very difficult; the people of Ai suspected nothing; probably the force on the east were at pains, by camp-fires and otherwise, to engage their attention, and whenever that force began to move, as if for the attack, every eye in the city would be fixed intently upon it.