The Sin of Achan.

But the people of Israel broke faith in regard to the devoted things, for Achan the son of Carmi, son of Zabdi, son of Zerah, of the tribe of Judah, took some of the devoted things. And the anger of the Lord burned against the people of Israel. (Joshua 7: 1)

Before the fall of Jericho, Joshua commanded the people of Israel as below.

And the city and all that is within it shall be devoted to the Lord for destruction. Only Rahab the prostitute and all who are with her in her house shall live, because she hid the messengers whom we sent. But you, keep yourselves from the things devoted to destruction, lest when you have devoted them you take any of the devoted things and make the camp of Israel a thing for destruction and bring trouble upon it. (Joshua 6: 17 18)

So, the Israelites did exactly as commanded except Achan. Without knowing it, Joshua also made an oath as below.

Joshua laid an oath on them at that time, saying, “Cursed before the Lord be the man who rises up and rebuilds this city, Jericho. At the cost of his firstborn shall he lay its foundation, and at the cost of his youngest son shall he set up its gates.” So the Lord was with Joshua, and his fame was in all the land. (Joshua 6: 26 27)

Yet God didn't reveal His wrath until they spied and attacked Ai as below.

And they returned to Joshua and said to him, “Do not have all the people go up, but let about two or three thousand men go up and attack Ai. Do not make the whole people toil up there, for they are few.” So about three thousand men went up there from the people. And they fled before the men of Ai, and the men of Ai killed about thirty-six of their men and chased them before the gate as far as Shebarim and struck them at the descent. And the hearts of the people melted and became as water. (Joshua 7: 3 to 5)

We may wonder why God punishes the whole Israeli army for one person's fault? First of all, they didn't search for God's guidance but took things into their own hands prior to the fight. Secondly, they were too confident to send just two or three thousand men while the city of Ai had twelve thousand people as we learned later. After realizing something must be wrong, Joshua tore his clothes and fell to the earth on his face and pleaded to God. Then God responded to him as below.

Israel has sinned; they have transgressed my covenant that I commanded them; they have taken some of the devoted things; they have stolen and lied and put them among their own belongings. Therefore the people of Israel cannot stand before their enemies. They turn their backs before their enemies, because they have become devoted for destruction. I will be with you no more, unless you destroy the devoted things from among you. (Joshua 7: 11 to 12)

So, to find the culprit, Joshua summoned Israel to God, tribe by tribe, clan by clan, and man by man until God took Achan. Then Joshua faced Achan and Achan responded as below.

And Achan answered Joshua, “Truly I have sinned against the Lord God of Israel, and this is what I did: when I saw among the spoil a beautiful cloak from Shinar, and 200 shekels of silver, and a bar of gold weighing 50 shekels, then I coveted them and took them. And see, they are hidden in the earth inside my tent, with the silver underneath.” (Joshua 7: 20 21)

Then Achan faced his fate as below.

And Joshua and all Israel with him took Achan the son of Zerah, and the silver and the cloak and the bar of gold, and his sons and daughters and his oxen and donkeys and sheep and his tent and all that he had. And they brought them up to the Valley of Achor. And Joshua said, “Why did you bring trouble on us? The Lord brings trouble on you today.” And all Israel stoned him with stones. They burned them with fire and stoned them with stones. (Joshua 7: 24 25)

We may think that the punishment was too harsh since at least Achan risked his life to fight those battles. That's because while building His army, God won't let any evil or sin hinder the holiness and righteousness He tried to imbed in them. The same thing happened to the story of the couple, Ananias and Sapphira. They sold a piece of property but kept some of the proceeds and brought only a part of it and laid it at the apostles' feet pretending to be the whole proceeds. The apostle Peter encountered them as below.

But Peter said, “Ananias, why has Satan filled your heart to lie to the Holy Spirit and to keep back for yourself part of the proceeds of the land? While it remained unsold, did it not remain your own? And after it was sold, was it not at your disposal? Why is it that you have contrived this deed in your heart? You have not lied to man but to God.” When Ananias heard these words, he fell down and breathed his last. (Acts 5: 3 to 5)

Later, Sapphire died the same way. It was because while building the church of Christ, the Holy Spirit won't let any evil endured by the deceitful sin to be on his way. That's how holy God wants his church to be. Immanuel.