Matthew Henry on Joshua 8:3-22
We have here an account of the taking of Ai by stratagem. The stratagem here used, we are sure, was lawful and good; God himself appointed it, and we have no reason to think but that the like is lawful and good in other wars. Here was no league broken, no treaty of peace, that the advantage was gained; no, these are sacred things, and not to be jested with, nor used to serve a turn; truth, when once it is plighted, becomes a debt even to the enemy. But in this stratagem here was no untruth told; nothing was concealed but their own counsels, which no enemy ever pretended a right to be entrusted with; nothing was dissembled, nothing counterfeited but a retreat, which was no natural or necessar…
Read the whole note in the consoleJamieson-Fausset-Brown on Joshua 8:18
Joshua stretched out the spear that he had in his hand toward the city--The uplifted spear had probably a flag, or streamer on it, to render it the more conspicuous from the height where he stood. At the sight of this understood signal the ambush nearest the city, informed by their scouts, made a sudden rush and took possession of the city, telegraphing to their brethren by raising a smoke from the walls. Upon seeing this, the main body, who had been reigning a flight, turned round at the head of the pass upon their pursuers, while the twenty-five thousand issuing from their ambuscade, fell back upon their rear. The Ai-ites surprised, looked back, and found their situation now desperate.
Adam Clarke on Joshua 8:18
Stretch out the spear - It is very probable that Joshua had a flag or ensign at the end of his spear, which might be easily seen at a considerable distance; and that the unfurling or waving of this was the sign agreed on between him and the ambush. (see Jos 8:13, and the preceding observations on Jos 8:1 (note), observation 6); and on seeing this flag or ensign unfurled, the men who lay in ambush arose and entered the city, making the fire previously agreed on. See Jos 8:8.
John Gill on Joshua 8:18
And the Lord said unto Joshua, stretch out the spear that is in thy hand towards Ai,.... On which was a flag, as Abarbinel and Ben Melech think; and which is not improbable, and served for a signal for the ambush to come out and seize the city, as both they and Jarchi observe, as well as a signal also to the army of Israel to prepare to turn and face about, and engage with the enemy; though they did not actually do this until they saw the smoke of the city, Joshua 8:21,
for I will give it into thine hand; of which the stretching out of his spear seems also to be a confirming sign to him, and which he kept stretched out until all the inhabitants of Ai were destroyed, Joshua 8:26,
and Joshua…