Joshua 8:1

And the Lord said unto Joshua
Immediately after the execution of Achan, the fierceness of his anger being turned away:

fear not, neither be thou dismayed;
on account of the defeat of his troops he had sent to take Ai:

take all the people of war with thee;
all above twenty years of age, which, with the forty thousand of the tribes on the other side Jordan he brought over with him, must make an arm, five hundred thousand men; these Joshua was to take with so much to animate and encourage him, or to terrify the enemy, nor because such a number was necessary for the reduction of Ai, which was but a small city; but that all might have a part in the spoil and plunder of it, which they were denied at Jericho, and chiefly to draw all the men out of the city, seeing such a numerous host approaching:

and arise, go up to Ai;
which lay high, and Joshua being now in the plains of Jericho, (See Gill on Joshua 7:2);

see, I have given into thy hand the king of Ai, and his people, and
his city, and his land;
this city, though a small one, had a king over it, as most cities in the land of Canaan had; the number of his people in it were twelve thousand, and his land were the fields about it; all which were given to Joshua by the Lord, and were as sure as if he had them already in his hand.