In the late 14th or early 15th century BC, it appears that the rumor mills were in working order. Israel under Joshua had finished conquering Canaan and the land was all divided up as it should be. Joshua told the tribes of Reuben, Gad, and Manasseh that they had done well, thank you very much, and they could go to their homes (Josh 22:1-6). They were going to be living on the east side of the Jordan, you see, but they had crossed the Jordan with the rest to help them take Canaan. That accomplished, they headed home. Unfortunately, before they crossed the Jordan, they stopped and built "a large altar" (Josh 22:10). Then they went home. Why "unfortunately"? Well, as soon as the rest of Israel heard about it, they took up arms. No, I'm not exaggerating. They weren't just filled with righteous indignation.
When the sons of Israel heard of it, the whole congregation of the sons of Israel gathered themselves at Shiloh to go up against them in war (Josh 22:12).Now, of course, we don't get it today. "Really, guys? War?" If it had happened today, we would have said, "Hey, live and let live. Let them do what they want. It's not our problem." To those who got upset, we would have said, "If they want to degenerate into what you consider sin, what business is that of yours? Judge not! Let's just agree to disagree." And we would be wrong. War, in this case, could be just. War, in this case, would be right. If Reuben and Gad and Manasseh had set out to rebel against God and Israel, a war was exactly the right prescription.
Now, if you read the rest of the account, you'll find out why. Before the shooting began (so to speak), they (wisely) chose to send a delegation to find out what in the world was going on! Phinehas, the son of Eleazar the priest, and a delegate from each of the 10 tribes went over and confronted their fellow Israelites on the east side of the Jordan. "What are you doing??!!" they said. "Why are you being unfaithful to God? Don't you remember Peor?" (Num 25 -- where they joined themselves to Baal and turned away God's anger by killing everyone who did ... and Phinehas was part of it.) "Don't you remember Achan? Look, guys, Achan's sin didn't only cost Achan. It cost all of us along with him and his family." In other words, idolatry hurts. It hurts everyone. And it cannot be faced with ambivalence or apathy. It demands a response.
Fortunately, Reuben, Gad, and Manasseh agreed. They hadn't built the altar for sacrificial purposes. They built it to remind everyone that they were the Lord's, that they worshiped on the west side of Jordan, that they were part of Israel (Josh 22:21-29). It was okay. It was good. The dialog managed to avoid the war. Fine. Good. Happy ending.
The story serves as a great example of managing conflict. Tell the other what you think the problem is. Listen to their response. Work together at solving the conflict. All good things. But I really want you to come away with the passion for the glory of God and the hatred for idolatry that they had. It's not "a bad idea", "a sin", "a bad thing". It's horrible, dangerous to everyone around, worthy of doing battle. Our modern "Let's not say anything and maybe it will go away" approach isn't working. I'm not advocating taking up arms, but we can see in the decline of the country and the decline of the church that we lack the passion for God that we must have. "Do nothing" is not working well. Perhaps we ought to consider a more biblical approach (like, for instance, Rev 2:2; Matt 18:15-17; 1 Cor 5:9-13).