18 And the Lord said to Joshua, Let your spear be stretched out against Ai; for I will give it into your hands. So Joshua took up his spear, stretching it out in the direction of the town. 19 Then the secret force came quickly from their place, and running forward when they saw his hand stretched out, went into the town and took it, and put fire to it straight away.
Matthew Henry's Commentary on Joshua 8:18-19
Commentary on Joshua 8:3-22
(Read Joshua 8:3-22)
Observe Joshua's conduct and prudence. Those that would maintain their spiritual conflicts must not love their ease. Probably he went into the valley alone, to pray to God for a blessing, and he did not seek in vain. He never drew back till the work was done. Those that have stretched out their hands against their spiritual enemies, must never draw them back.