The Altar by the Jordan
The land has been apportioned, and the eastern tribes have fulfilled their responsibilities. Joshua now dismisses them to return home. The time and sacrifice has not been without its rewards, as they return with much wealth from the spoils of Canaan, which Joshua urges them to share with those who remained to take care of their land and families (verse 8). Before they go, Joshua exhorts them to follow God’s law wholeheartedly (verse 5). So it comes as a great shock when word comes back that they have built a large altar beside the Jordan River apparently contrary to God’s explicit commands (compare Deuteronomy 12). In their zeal, a war party forms at Shiloh to deal with this brazen transgression. Before heading off to battle, a delegation of tribal leaders, headed by Phinehas, the son of the high priest, is sent to find out just why they have done this. The delegation reminds them of some of Israel’s past transgressions, and suggests that perhaps it would be better if they came over to the western lands after all.
The tribes explain, however, that things are not how they look to the western delegation. They say they built it as a “replica of the altar of the Lord which our fathers made” (Joshua 22:28 Joshua 22:28Therefore said we, that it shall be, when they should so say to us or to our generations in time to come, that we may say again, Behold the pattern of the altar of the LORD, which our fathers made, not for burnt offerings, nor for sacrifices; but it is a witness between us and you.
American King James Version×), i.e., apparently a copy of the stone one that had been set up at Mount Ebal (compare Joshua 8:30-31 Joshua 8:30-31  Then Joshua built an altar to the LORD God of Israel in mount Ebal,  As Moses the servant of the LORD commanded the children of Israel, as it is written in the book of the law of Moses, an altar of whole stones, over which no man has lift up any iron: and they offered thereon burnt offerings to the LORD, and sacrificed peace offerings.
American King James Version×). And, most importantly, this altar, they maintain, was not to be used for sacrifices as the original was, but rather to serve as a witness and reminder in years to come to Israelites on both sides of the Jordan that they too are a part of Israel, who also worship the true God (Joshua 22:27-28 Joshua 22:27-28  But that it may be a witness between us, and you, and our generations after us, that we might do the service of the LORD before him with our burnt offerings, and with our sacrifices, and with our peace offerings; that your children may not say to our children in time to come, You have no part in the LORD.  Therefore said we, that it shall be, when they should so say to us or to our generations in time to come, that we may say again, Behold the pattern of the altar of the LORD, which our fathers made, not for burnt offerings, nor for sacrifices; but it is a witness between us and you.
American King James Version×). The explanation is quite acceptable to Phinehas and the tribal leaders. They return to Shiloh, and a civil war is averted (verses 30-34).