Notes on the Bible, by Albert Barnes, [1834], at sacred-texts.com
God rouses Joshua from his dejection Jos 7:6, and bids him lmarch against Ai with the main body. Though Ai was but a small city (compare Jos 8:25 and Jos 7:3), yet the discouragement of the people rendered it inexpedient to send a second time a mere detachment against it; and the people of Ai had, as appears from Jos 8:17, help from Bethel, and possibly from other places also. It was fitting too that all the people should witness with their own eyes the happy consequences of having faithfully put away the sin which had separated them from God.
Thirty thousand men - comparing Jos 8:3 and Jos 8:12 ("five thousand men"), there is probably a mistake in the numbers of this verse, where an early copyist may have written the sign for 30,000 instead of that for 5,000.
Sent them away by night - The selected 5,000 would accordingly post themselves in the main ravine between Ai and Bethel in the night and early morning. The neighhorhood in which Ai was situated is described as "a wild entanglement of hill and valley;" and amidst its recesses the detachment could easily shelter itself from observation until Joshua's other measures were taken.
Numbered the people - Rather, perhaps, "mustered" or "arrayed" them for their march. The distance from the camp at Gilgal to Ai is about fifteen miles. In the evening of the day after the despatch of the 5,000 liers in wait, Joshua and the host might make their appearance in the neighborhood of the city.
He took - Rather "had taken;" the words refer to the ambuscade which Joshua had detached during the previous night.
Joshua went down by night into the valley where He would be seen at daylight by the men of Ai, and was accompanied no doubt by a picked body of troops. The king of Ai, in the morning, would see neither the ambush in his rear, nor the whole of the great host of Israel among the hills away to the north on his left; but supposing, as it appears, that the Israelites before him were a body detached as on the former occasion to assail his city, he sallied out promptly to attack them.
At a time appointed - Rather, "at the place appointed," i. e. some spot suitable for the drawing up of his men, which had been assigned beforehand. This was "before the plain," i. e. it was at the entrance of the depressed tract of land which runs down to the Jordan valley, up which lay the route of the Israelites from Gilgal to Ai.
Or Bethel - See the Jos 8:1 note.
No doubt Joshua had ascended the heights, most likely those to the north of the valley, so as to separate himself from the flying Israelites on the lower ground, and to be visible to the men in ambush behind the city. He now, at the command of God, gives the appointed signal to the ambush.
Compare Deu 21:22-23 notes.
The account of this solemnity is very brief. An acquaintance with Deut. 27 is evidently presupposed; and the three several acts of which the solemnity consisted are only so far distinctly named as is necessary to show that the commands of Moses there given were fully carried out by Joshua.
It is difficult to escape the conviction that these verses are here out of their proper and original place. The connection between Jos 8:29, and Jos 9:1, is natural and obvious; and in Jos 9:3, the fraud of the Gibeonites is represented as growing out of the alarm caused by the fall of Jericho and Ai. It is, moreover, extremely unlikely that a solemnity of this nature in the very center of the country should be undertaken by Joshua while the whole surrounding district was in the hands of the enemy; or that, if undertaken, it would have been carried out unmolested. "And the strangers that were conversant among them" Jos 8:35, were present at it. The distance fromm Gilgal in the Jordan valley to Mount Ebal is fully 30 miles, unless - as is unlikely - another Gilgal (Deu 11:29 note) be meant; and so vast a host, with its non-effective followers Jos 8:35, could certainly not have accomplished a march like this through a difficult country and a hostile population in less than three days. Moreover in Jos 9:6; Jos 10:6, Jos 10:15, Jos 10:43, the Israelites are spoken of as still encamping at Gilgal.
It is on the whole likely that, for these and other reasons, this passage does not, in our present Bible, stand in its proper context; and it has been conjectured that the place from which these six verses have been transferred is the end of Josh. 11: The "then" with which Jos 8:30 opens in our present text may well have served to introduce the account of the solemnity on Gerizim and Ebal at the end of the record of Joshua's victories, to which indeed it forms a suitable climax.
See the note marginal reference.
All the words of the law - See Deu 31:11 ff It would seem that Joshua, on the present occasion, must have read at least all the legislative portion of the Pentateuch before the people (compare on Deu 27:3). The terms of this verse cannot be satisfactorily explained as importing only the blessings and curses of Deut. 27-28.