Joshua 8:17

13 So the forces were stationed with the main camp to the north of the city and the rear guard to the west of the city. And that night Joshua went into the valley.

14 When the king of Ai saw the Israelites, he hurried out early in the morning with the men of the city to engage them in battle at an appointed place overlooking the Arabah. But he did not know that an ambush had been set up against him behind the city.

15 Joshua and all Israel let themselves be beaten back before them, and they fled toward the wilderness.

16 Then all the men of Ai were summoned to pursue them, and they followed Joshua and were drawn away from the city.

17 Not a man was left in Ai or Bethel who did not go out after Israel, leaving the city wide open while they pursued Israel.

18 Then the LORD said to Joshua, “Hold out your battle lance toward Ai, for into your hand I will deliver the city.” So Joshua held out his battle lance toward Ai,

19 and as soon as he did so, the men in ambush rose quickly from their position. They rushed forward, entered the city, captured it, and immediately set it on fire.

20 When the men of Ai turned and looked back, the smoke of the city was rising into the sky. They could not escape in any direction, and the troops who had fled to the wilderness now became the pursuers.

21 When Joshua and all Israel saw that the men in ambush had captured the city and that smoke was rising from it, they turned around and struck down the men of Ai.

Read all of Joshua 8