Matthew Henry Commentary Joshua 7:1-5

"But the children of Israel committed a trespass in the devoted thing; for Achan, the son of Carmi, the son of Zabdi, the son of Zerah, of the tribe of Judah, took of the devoted thing: and the anger of Jehovah was kindled against the children of Israel. And Joshua sent men from Jericho to Ai, which is beside Beth-aven, on the east side of Beth-el, and spake unto them, saying, Go up and spy out the land. And the men went up and spied out Ai. And they returned to Joshua, and said unto him, Let not all the people go up; but let about two or three thousand men go up and smite Ai; make not all the people to toil thither; for they are but few. So there went up thither of the people about three thousand men: and they fled before the men of Ai. And the men of Ai smote of them about thirty and six men; and they chased them [from] before the gate even unto Shebarim, and smote them at the descent; and the hearts of the people melted, and became as water." — Joshua 7:1-5 (ASV)

Achan took some of the spoil of Jericho. The love of the world is that root of bitterness which, more than any other, is most difficult to root up. We should beware of sin ourselves, lest by it many are defiled or troubled (Hebrews 12:15); and we should also beware of having fellowship with sinners, lest we share their guilt.

It is important for us to watch over one another to prevent sin, because others' sins may be to our harm. The easy conquest of Jericho aroused contempt for the enemy and an inclination to expect the Lord to do everything for them, without them using appropriate means. In this way, people abuse the doctrines of divine grace and the promises of God, turning them into excuses for their own sloth and self-indulgence.

We are to work out our own salvation, though it is God who works in us. It was a costly victory for the Canaanites, by which Israel was awakened and reformed, and reconciled to their God, while the people of Canaan were hardened towards their own ruin.