30 At that time Joshua built an altar to the Lord, the God of Israel, on Mount Ebal, 31 just as Moses the servant of the Lord had commanded the people of Israel, as it is written in the Book of the Law of Moses, “an altar of uncut stones, upon which no man has wielded an iron tool.” And they offered on it burnt offerings to the Lord and sacrificed peace offerings. 32 And there, in the presence of the people of Israel, he wrote on the stones a copy of the law of Moses, which he had written. 33 And all Israel, sojourner as well as native born, with their elders and officers and their judges, stood on opposite sides of the ark before the Levitical priests who carried the ark of the covenant of the Lord, half of them in front of Mount Gerizim and half of them in front of Mount Ebal, just as Moses the servant of the Lord had commanded at the first, to bless the people of Israel. 34 And afterward he read all the words of the law, the blessing and the curse, according to all that is written in the Book of the Law. 35 There was not a word of all that Moses commanded that Joshua did not read before all the assembly of Israel, and the women, and the little ones, and the sojourners who lived among them. 
Most Old Testament students agree that the heart of the Old Testament law is the book of Deuteronomy and that the heart of Deuteronomy is the list of blessings and curses found in chapters 27 through 30. Undergirding Deuteronomy is the unconditional Covenant of Grace God made with Abraham by which the Jews were chosen to be God’s people from whom would come the Promised Seed who would undo the work of the devil (Genesis 3:15).
The book of Deuteronomy is a republication of God’s holy Law, his Covenant of Works wherein blessing, or lack of blessing, depends upon obedience. On one hand, there is a list of curses for those who disobey God’s law (Deuteronomy 27-28). On the other hand, there is a list of blessings for those who obey it (Deuteronomy 28). Those two chapters are followed by two more chapters that call for a renewal of the Covenant of Works and end with a call to the people to choose the way of God’s blessing.
Moses proclaims, “This day I call heaven and earth as witnesses against you that I have set before you life and death, blessings and curses. Now choose life, so that you and your children may live and that you may love the Lord your God, listen to his voice, and hold fast to him” (Deuteronomy 30:19-20). This was the last instruction the people received from Moses before they crossed over the Jordan River into the Promised Land.
BLESSINGS AND CURSES
The listing of blessings and curses in Deuteronomy was not only preached to the Jewish people by Moses before beginning their conquest of Canaan, but was also repeated in a special, ceremonial way once they were in the new land. Scripture does not record that Moses had ever been in Canaan, but he knew something about it. So he said that when the people of Israel came into the land, they were to read these blessings and curses at a special assembly on the sides of Mounts Ebal and Gerizim. Joshua did this.
Ai stood at the high western end of the approach to the Hill Country from the Jordan Valley. In order to conquer Canaan, the Israelites had to control the mountain road running north and south through its highest regions. And in order to take the road, they had to move upward to it past Jericho and Ai. Jericho controlled the approach from the east, from the lower area of the Jordan river. Ai controlled the higher western end of this approach.
Following their two victories, we might have expected Israel’s army to proceed immediately with the conquest of the country by moving south along the mountain road to attack the most heavily fortified cities of that region. They will do this eventually. But now in our story, they take a detour of about 25 miles north and a few miles west to a valley located between Mount Ebal and Mount Gerizim.
The mountains are about 3,000 feet above sea level, 1,000 feet above the valley between them. They are bald and barren. But the valley is often green. At one place where the feet mountains come together, there is a natural amphitheater capable of containing a vast audience. By order of Moses, this amphitheater was the people’s destination. Here they camped out for the ceremony. It is said to be a place of fine natural acoustic properties. Just two people, standing on opposite mountains can hear the other quite clearly.
The people gathered for their ceremony in precise obedience to the earlier commands of Moses. Moses had said, “When you have crossed the Jordan, these tribes shall stand on Mount Gerizim to bless the people: Simeon, Levi, Judah, Issachar, Joseph and Benjamin. And these tribes shall stand on Mount Ebal to pronounce curses: Ruben, Gad, Asher, Zebulun, Dan and Naftali” (Deut. 27:12-13). The Levites were to read the curses:
Cursed is the man who carves an image or casts an idol—a thing detestable to the Lord, the work of the craftsman’s hands—and sets it up in secret.…
Cursed is the man who dishonors his father or his mother.…
Cursed is the man who moves his neighbor’s boundary stone.…
Cursed is the man who leads the blind astray on the road.…
Cursed is the man who withholds justice from the alien, the fatherless or the widow.…
Cursed is the man who sleeps with his father’s wife, for he dishonors his father’s bed.…
Cursed is the man who has sexual relations with any animal.…
Cursed is the man who sleeps with his sister, the daughter of his father or the daughter of his mother.…
Cursed is the man who sleeps with his mother-in-law.…
Cursed is the man who kills his neighbor secretly.…
Cursed is the man who accepts a bribe to kill an innocent person.…
Cursed is the man who does not uphold the words of this law by carrying them out.…
After each of the 12 curses were read by the Levites, the people were to agree to the truth of the statements by responding, “Amen.” Then the covenant blessings were to be read:
If you fully obey the Lord your God and carefully follow all his commands I give you today, the Lord your God will set you high above all the nations on earth. All these blessings will come upon you and accompany you if you obey the Lord your God:
You will be blessed in the city and blessed in the country.
The fruit of your womb will be blessed, and the crops of your land and the young of your livestock—the calves of your herds and the lambs of your flocks.
Your basket and your kneading trough will be blessed.
You will be blessed when you come in and blessed when you go out.
The Lord will grant that the enemies who rise up against you will be defeated before you. They will come at you from one direction but flee from you in seven.
The author of Joshua describes how Joshua organized the ceremony exactly as Moses had commanded:
33 And all Israel, sojourner as well as native born, with their elders and officers and their judges, stood on opposite sides of the ark before the Levitical priests who carried the ark of the covenant of the Lord, half of them in front of Mount Gerizim and half of them in front of Mount Ebal, just as Moses the servant of the Lord had commanded at the first, to bless the people of Israel. 34 And afterward he read all the words of the law, the blessing and the curse, according to all that is written in the Book of the Law. 35 There was not a word of all that Moses commanded that Joshua did not read before all the assembly of Israel, and the women, and the little ones, and the sojourners who lived among them (8:33-35).
In the valley in between the two mountains was the settlement of Shechem. Imagine how the people of that village felt as the army of Israel assembled above and in between them shouting out their testimony to YHWH. The Levites even left God’s Law written on the rocks of the mountains.
From the garden of Eden to the sin of Achan to the shouting of blessing and cursing, we see an enduring principle in the Covenant of Works: blessing for obedience and cursing for disobedience. It teaches something of the very character of God. He is absolutely perfect, and he demands perfection from all people.
When the Israelites entered the land and commenced their attack on Jericho in strict obedience to the commands of God, the result was unprecedented blessing. It was exactly what should have been expected since God was directing the battle. The people were obedient. God is benevolent and desired to bless them with the victory. And God was all powerful and completely capable of delivering that victory.
But when the people moved up from Jericho to attack Ai and suffered an inglorious defeat, it was immediately apparent that something had gone wrong. There was disobedience in the camp. Only after the sin was exposed and judgment meted out to the offender did blessing return. It is a brutal life to live under the constant demand for perfection and the real and present danger of judgment. This explains not only the Israelite experience in the wilderness and in the promised land, but it also explains the period of the judges and kings, the captives under Assyria and Babylon, the Jews returned from Babylon, and the final dispersion in AD 70. It also explains much of our experience today.
The covenant renewal ceremony teaches us more than the Covenant of Works principle that obedience leads to blessing and disobedience to cursing. It also teaches God’s solution to the problem of sin in any person’s life.
If you have listened and followed along in your Bible carefully, you may have noticed the part of these verses describing the reading of the law (8:30-32) is preceded by a section that tells of the construction of an altar on which the law was written (8:30-32). This also was in fulfillment of God’s commands given through Moses. In Deuteronomy 27:2-8, Moses said:
2 And on the day you cross over the Jordan to the land that the Lord your God is giving you, you shall set up large stones and plaster them with plaster. 3 And you shall write on them all the words of this law, when you cross over to enter the land that the Lord your God is giving you, a land flowing with milk and honey, as the Lord, the God of your fathers, has promised you. 4 And when you have crossed over the Jordan, you shall set up these stones, concerning which I command you today, on Mount Ebal, and you shall plaster them with plaster. 5 And there you shall build an altar to the Lord your God, an altar of stones. You shall wield no iron tool on them; 6 you shall build an altar to the Lord your God of uncut stones. And you shall offer burnt offerings on it to the Lord your God, 7 and you shall sacrifice peace offerings and shall eat there, and you shall rejoice before the Lord your God. 8 And you shall write on the stones all the words of this law very plainly.”
Joshua 8:30-32 is the fulfillment of this command:
30 At that time Joshua built an altar to the Lord, the God of Israel, on Mount Ebal, 31 just as Moses the servant of the Lord had commanded the people of Israel, as it is written in the Book of the Law of Moses, “an altar of uncut stones, upon which no man has wielded an iron tool.” And they offered on it burnt offerings to the Lord and sacrificed peace offerings. 32 And there, in the presence of the people of Israel, he wrote on the stones a copy of the law of Moses, which he had written.
There are several reasons that make this such a glorious picture. On this solemn occasion when the Law of Moses was visibly held before the people by the written law on the stones and by the reciting of the law by the Levites (and the response of the people to the readings), the altar was constructed as the solution to a very glaring problem: absolutely no one could keep the Covenant of Works perfectly as God demanded because all human beings are born into the condition of sin.
This is what God had been teaching the Israelites all along. When God gave the law to Moses on Sinai, he gave at the same time the regulations regarding sacrifices. When he gave Moses to be the law giver, he gave Aaron at the same time to be the high priest. The law demanded, “Do this and live, do that and die.” The altar demanded, “Flee here, repent, and trust into the grace of your great redeeming God.”
Sin brings judgment. The judgment of sin is death. But the sacrifices show it’s possible for an innocent victim to die in the place of the sinner. In those ancient days, the victim was an animal. But the animal was a type, a shadow, pointing forward to the only truly sufficient sacrifice, the sacrifice of the Lord Jesus Christ. He lived the only perfectly law-keeping life any human being has ever lived. He alone has kept the Covenant of Works. He was the only truly innocent, sinless, willing victim through whose death we may escape sin’s punishment.
Another reason this picture is so glorious is that when the altar was constructed by Joshua in obedience to the commands of Moses, it was not constructed in the valley between the two mountains. Nor was it constructed on Mount Gerizim, the mount of blessing. It was constructed on Mount Ebal, the mountain of cursing. In other words, the altar was for sinners condemned for breaking God’s Covenant of Works. Mount Ebal, with its sacrificial altar, was for sinners. It was for those who acknowledged their sin and who came, not as the righteous expecting blessing, but as sinners deserving the curses of the law. There, on that altar, they would watch an innocent victim die in their place.
Interestingly, 1000 years later the Samaritans built their altar on Gerizim, not Ebal. The Samaritans, like so many spiritually impoverished people today, built their altar on the mount of good works. So, when the woman of Samaria told Jesus, “Our fathers worshipped on this mountain, but you Jews claim that the place where we must worship is in Jerusalem,” she was pointing to Gerizim. Jesus responded by turning her away from that mountain as well as from Mount Zion to himself and his coming sacrifice.
The chief characteristic of the Samaritans of that day, and their spiritual descendants in our day, is self-righteousness. The Samaritans would not come to God as sinners, confessing their need of a cleansing, substitutionary sacrifice. They came as “mostly” righteous people. Consequently, the first thing Jesus did with the woman at the well was to expose her spiritual ignorance: “You Samaritans worship what you do not know” (John 4:22). Also, he uncovered her sin: “You have had five husbands, and the man you now have is not your husband” (4:18).
The final aspect of this glorious picture is that the altar constructed on Mount Ebal was to be of natural stones with no human workmanship added to them. The stones were not to be cut or shaped by human effort. God made the rubble of Jericho. God made the rubble of Ai (The Rubble Pile). Now, God alone provides the rubble for his altar from the rocks of Mount Ebal. The only alteration God commanded was that the rocks be painted over with limestone, whitewashed, so that the words of his Covenant of Works were clearly visible both to the Israelites and to the pagans living in or passing through Shechem.
It is not just a matter of coming to God as a sinner, acknowledging your rightful place as a sinner on Mount Ebal. That is most certainly essential, but it is not enough. Nor is it enough to come to the place of sacrifice, acknowledging your need for another to die for you. The Samaritans came to an altar and offered up sacrifices to add to what they believed to be their own good works. It is essential to acknowledge that something innocent must die in your place, but it’s still not enough. In addition to these absolutely essential things, you must come to acknowledge that there is nothing, absolutely nothing, that you can contribute to the effort of your right standing with God.
The reformers express this truth with the phrases “by faith alone” and “by grace alone.” That is, faith in the work of God alone and not faith that is in any way linked to human effort or human merit. It is God’s gracious work from start to finish. Only he is entirely sufficient for our redemption out of bondage to sin. “Nothing in my hand I bring, simply to thy cross I cling; naked come to thee for dress, helpless look to thee for grace; foul, I to the Fountain fly; wash me, Savior, or I die. Rock of Ages, cleft for me, let me hide myself in thee.”
Christ’s cross is that fountain. His cross is the rugged altar. He is the rock, cleft for us. If we come to him, we will have shelter and cleansing. And we will receive power to begin to live in a way that reflects the blessings we have been freely given. St Author of Hebrews sums it up this way:
For since the law has but a shadow of the good things to come instead of the true form of these realities, it can never, by the same sacrifices that are continually offered every year, make perfect those who draw near. 2 Otherwise, would they not have ceased to be offered, since the worshipers, having once been cleansed, would no longer have any consciousness of sins? 3 But in these sacrifices there is a reminder of sins every year. 4 For it is impossible for the blood of bulls and goats to take away sins.
5 Consequently, when Christ came into the world, he said, “Sacrifices and offerings you have not desired, but a body have you prepared for me; 6 in burnt offerings and sin offerings you have taken no pleasure. 7Then I said, ‘Behold, I have come to do your will, O God, as it is written of me in the scroll of the book.’”
8 When he said above, “You have neither desired nor taken pleasure in sacrifices and offerings and burnt offerings and sin offerings” (these are offered according to the law), 9 then he added, “Behold, I have come to do your will.” He does away with the first in order to establish the second. 10 And by that will we have been sanctified through the offering of the body of Jesus Christ once for all. 
 The Holy Bible: English Standard Version (Wheaton, IL: Crossway Bibles, 2016), Jos 8:30–35.
 Boice, 65.
 Id., 66.
 Deuteronomy 27:15-26.
 Deuteronomy 28:1-7
 The Holy Bible: English Standard Version (Wheaton, IL: Crossway Bibles, 2016), Heb 10:1–10.