Destruction of Ai
God commands Joshua to stretch out his spear toward the city of Ai (verse 18). Not only was this a signal to begin the attack (verse 19), but it was also a symbol of God's presence and help to His people in the battle (compare verses 1, 18)—displayed in the fact that Joshua did not lower his spear until the victory was won (verse 26). This is powerfully reminiscent of Israel's first battle upon leaving Egypt against the Amalekites, where Moses held aloft the rod of God, which was also a symbol of God's participation in the battle (Exodus 17:8-16 Exodus 17:8-16  Then came Amalek, and fought with Israel in Rephidim.
 And Moses said to Joshua, Choose us out men, and go out, fight with Amalek: to morrow I will stand on the top of the hill with the rod of God in my hand.
 So Joshua did as Moses had said to him, and fought with Amalek: and Moses, Aaron, and Hur went up to the top of the hill.
 And it came to pass, when Moses held up his hand, that Israel prevailed: and when he let down his hand, Amalek prevailed.
 But Moses hands were heavy; and they took a stone, and put it under him, and he sat thereon; and Aaron and Hur stayed up his hands, the one on the one side, and the other on the other side; and his hands were steady until the going down of the sun.
 And Joshua discomfited Amalek and his people with the edge of the sword.
 And the LORD said to Moses, Write this for a memorial in a book, and rehearse it in the ears of Joshua: for I will utterly put out the remembrance of Amalek from under heaven.
 And Moses built an altar, and called the name of it Jehovahnissi:
 For he said, Because the LORD has sworn that the LORD will have war with Amalek from generation to generation.
American King James Version×). Remarkably, Joshua had been the military commander in that former battle, looking to Moses with the rod. Now here he was with raised spear, standing as the one others were looking to. Of course, it was recognized in both instances that God was the one directing the outcome.
Along with the defeat of Ai, the city of Bethel is also mentioned (verse 17). "Bethel was near Ai to the west (Joshua 7:2 Joshua 7:2And Joshua sent men from Jericho to Ai, which is beside Bethaven, on the east of Bethel, and spoke to them, saying, Go up and view the country. And the men went up and viewed Ai.
American King James Version×), although its exact site is disputed. The inhabitants of Bethel came out of their city to help the men of Ai. Since the Israelite ambush was stationed between Bethel and Ai [Joshua 8:12 Joshua 8:12And he took about five thousand men, and set them to lie in ambush between Bethel and Ai, on the west side of the city.
American King James Version×], they may have felt threatened by the Israelites. Or it may be that Ai was a small outpost for the larger city of Bethel (Joshua 7:3 Joshua 7:3And they returned to Joshua, and said to him, Let not all the people go up; but let about two or three thousand men go up and smite Ai; and make not all the people to labor thither; for they are but few.
American King James Version×) and an attack on Ai was understood to be an attack on Bethel. The text does not record Bethel's defeat, although its king is listed among those conquered by Joshua (Joshua 12:16 Joshua 12:16The king of Makkedah, one; the king of Bethel, one;
American King James Version×). It may be that in the defeat of Ai, Bethel was also defeated and no further reference was needed" (Nelson Study Bible, note on Joshua 8:17 Joshua 8:17And there was not a man left in Ai or Bethel, that went not out after Israel: and they left the city open, and pursued after Israel.
American King James Version×).
Following the Israelites' defeat of Ai, Joshua led them to Shechem, which is between Mount Ebal and Mount Gerizim, near modern-day Nablus. There he carried out the commands of God and Moses to build an altar, erect massive stones engraved with the Book of the Law, review the law, and rehearse the blessings and curses (verses 30-35; compare Deuteronomy 11:29-32 Deuteronomy 11:29-32  And it shall come to pass, when the LORD your God has brought you in to the land where you go to possess it, that you shall put the blessing on mount Gerizim, and the curse on mount Ebal.
 Are they not on the other side Jordan, by the way where the sun goes down, in the land of the Canaanites, which dwell in the desert over against Gilgal, beside the plains of Moreh?
 For you shall pass over Jordan to go in to possess the land which the LORD your God gives you, and you shall possess it, and dwell therein.
 And you shall observe to do all the statutes and judgments which I set before you this day.
American King James Version×; Deuteronomy 27:1-26 Deuteronomy 27:1-26  And Moses with the elders of Israel commanded the people, saying, Keep all the commandments which I command you this day.  And it shall be on the day when you shall pass over Jordan to the land which the LORD your God gives you, that you shall set you up great stones, and plaster them with plaster:  And you shall write on them all the words of this law, when you are passed over, that you may go in to the land which the LORD your God gives you, a land that flows with milk and honey; as the LORD God of your fathers has promised you.  Therefore it shall be when you be gone over Jordan, that you shall set up these stones, which I command you this day, in mount Ebal, and you shall plaster them with plaster.  And there shall you build an altar to the LORD your God, an altar of stones: you shall not lift up any iron tool on them.  You shall build the altar of the LORD your God of whole stones: and you shall offer burnt offerings thereon to the LORD your God:  And you shall offer peace offerings, and shall eat there, and rejoice before the LORD your God.  And you shall write on the stones all the words of this law very plainly.  And Moses and the priests the Levites spoke to all Israel, saying, Take heed, and listen, O Israel; this day you are become the people of the LORD your God.  You shall therefore obey the voice of the LORD your God, and do his commandments and his statutes, which I command you this day.  And Moses charged the people the same day, saying,  These shall stand on mount Gerizim to bless the people, when you are come over Jordan; Simeon, and Levi, and Judah, and Issachar, and Joseph, and Benjamin:  And these shall stand on mount Ebal to curse; Reuben, Gad, and Asher, and Zebulun, Dan, and Naphtali.  And the Levites shall speak, and say to all the men of Israel with a loud voice,  Cursed be the man that makes any graven or molten image, an abomination to the LORD, the work of the hands of the craftsman, and puts it in a secret place. And all the people shall answer and say, Amen.  Cursed be he that sets light by his father or his mother. And all the people shall say, Amen.  Cursed be he that removes his neighbor's landmark. And all the people shall say, Amen.  Cursed be he that makes the blind to wander out of the way. And all the people shall say, Amen.  Cursed be he that perverts the judgment of the stranger, fatherless, and widow. And all the people shall say, Amen.  Cursed be he that lies with his father's wife; because he uncovers his father's skirt. And all the people shall say, Amen.  Cursed be he that lies with any manner of beast. And all the people shall say, Amen.  Cursed be he that lies with his sister, the daughter of his father, or the daughter of his mother. And all the people shall say, Amen.  Cursed be he that lies with his mother in law. And all the people shall say, Amen.  Cursed be he that smites his neighbor secretly. And all the people shall say, Amen.  Cursed be he that takes reward to slay an innocent person. And all the people shall say, Amen.  Cursed be he that confirms not all the words of this law to do them. And all the people shall say, Amen.
American King James Version×). Afterward, they apparently returned to Gilgal, where they first camped after crossing the Jordan (compare Joshua 9:6 Joshua 9:6And they went to Joshua to the camp at Gilgal, and said to him, and to the men of Israel, We be come from a far country: now therefore make you a league with us.
American King James Version×).
Supplementary Reading: "A Good News Interview With Bryant Wood, Ph.D.: The Bible vs. Modern Scholarship," The Good News, March-April 2002, pp. 12-13.