(3) And Joshua chose out thirty thousand mighty men.--Some difficulty arises from the fact that thirty thousand men are mentioned as having been sent away with general instructions to form an ambush in the first instance, while five thousand were ultimately posted between Bethel and Ai. Were there two distinct bodies in ambush, or only one? It does not seem possible to answer this question with absolute certainty; but we ought to notice in the first place what the aim of Joshua was. He meant to isolate the town of Ai, taking it in front and flank; but there was another town immediately in the rear, less than two miles off. It was necessary, therefore, to employ a sufficient body of men to close the communications between Bethel and Ai from the first.

Verse 3. - Thirty thousand. In ver. 12 we read 5,000, and this must be the true reading. Thirty thousand men could hardly have been posted, without detection, in the ravines around Ai, whereas we are informed by travellers that there would have been no difficulty in concealing 5,000 men there. See, however, the passage cited from Lieut. Conder's Report in the note on Joshua 7:2. The confused condition of the numbers in the present text of the Old Testament is a well known fact, and it is proved by the great discrepancies in this respect between the Books of Chronicles and those of Samuel and Kings. Some have thought (e.g., Haverniek, 'Introduction to the Old Testament,' II. 1:15) that two bands were laid in ambush, one on the northwest and the other on the southwest. This is a possible, though not probable, solution of the difficulty (see below). Then we must suppose that the city was nearly surrounded, Joshua and the main body on the southeast, the larger detachment on the north (ver. 13), and the smaller ambush on the west (see note on ver. 13). Keil, in his earlier editions, supposed that Joshua assaulted Ai with 30,000 men, out of whom he chose 5,000 as an ambush. So also Hengstenberg's 'Geschichte des Reiches Gottes,' p. 219. But this only introduces a third contradiction, for we are told both in vers. 1 and 3 that Joshua took with him "all the men of war." Keil has, however, abandoned that supposition, which is contrary to all the ancient versions, including the present text of the LXX. The Bishop of Lincoln suggests that 5,000 men may have been detached to reinforce the former detachment of 30,000. But to say nothing of the improbability of an ambush of 35,000 men remaining undetected (and they were specially instructed - see next verse - not to station themselves far from the city), we have the plain statement in ver. 12 וַיָּשֶׂם אותָם אורֵב "he stationed (or had stationed) them as an ambush."

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.So Joshua arose, and all the people of war, to go up against Ai,.... As the Lord had commanded him:

and Joshua chose out thirty thousand mighty men of valour; out of all the men of war; these were a select company, picked men, not the whole army, as some have thought, for he was ordered to take all the people of war, as he did:

and sent them away by night; from the main army, that they might pass the city and get behind it undiscovered, for they were sent for an ambush; and of these some were to take the city, and be left in it to burn it, and some to smite the men of Ai, as Abarbinel notes.