II. The camp of Israel suffering for the same: The anger of the Lord was kindled against Israel; he saw the offence, though they did not, and takes a course to make them see it; for one way or other, sooner or later, secret sins will be brought to light; and, if men enquire not after them, God will, and with his enquiries will awaken theirs. Many a community is under guilt and wrath and is not aware of it till the fire breaks out: here it broke out quickly. 1. Joshua sends a detachment to seize upon the next city that was in their way, and that was Ai. Only 3000 men were sent, advice being brought him by his spies that the place was inconsiderable, and needed no greater force for the reduction of it, v. 2, 3. Now perhaps it was a culpable assurance, or security rather that led them to send so small a party on this expedition; it might also be an indulgence of the people in the love of ease, for they will not have all the people to labour thither. Perhaps the people were the less forward to go upon this expedition because they were denied the plunder of Jericho; and these spies were willing they should be gratified. Whereas when the town was to be taken, though God by his own power would throw down the walls, yet they must all labour thither and labour there too, in walking round it. It did not bode well at all that God's Israel began to think much of their labour, and contrived how to spare their pains. It is required that we work out our salvation, though it is God that works in us. It has likewise often proved of bad consequence to make too light of an enemy. They are but few (say the spies), but, as few as they were, they were too many for them. It will awaken our care and diligence in our Christian warfare to consider that we wrestle with principalities and powers. 2. The party he sent, in their first attack upon the town, were repulsed with some loss (v. 4, 5): They fled before the men of Ai, finding themselves unaccountably dispirited, and their enemies to sally out upon them with more vigour and resolution than they expected. In their retreat they had about thirty-six men cut off: no great loss indeed out of such a number, but a dreadful surprise to those who had no reason to expect any other in any attack than clear, cheap, and certain victory. And now, as it proves, it is well there were but 3000 that fell under this disgrace. Had the body of the army been there, they would have been no more able to keep their ground, now they were under guilt and wrath, than this small party, and to them the defeat would have been much more grievous and dishonourable. However, it was bad enough as it was, and served, (1.) To humble God's Israel, and to teach them always to rejoice with trembling. Let not him that girdeth on the harness boast as he that putteth it off. (2.) To harden the Canaanites, and to make them the more secure notwithstanding the terrors they had been struck with, that their ruin, when it came, might be the more dreadful. (3.) To be an evidence of God's displeasure against Israel, and a call to them to purge out the old leaven. And this was principally intended in their defeat. 3. The retreat of this party in disorder put the whole camp of Israel into a fright: The hearts of the people melted, not so much for the loss as for the disappointment. Joshua had assured them that the living God would without fail drive out the Canaanites from before them, ch. iii. 10. How can this event be reconciled to that promise? To every thinking man among them it appeared an indication of God's displeasure, and an omen of something worse, and therefore no marvel it put them into such a consternation; if God turn to be their enemy and fight against them, what will become of them? True Israelites tremble when God is angry.