What does the Bible say about the altar built by the tribes of Israel?

In Joshua 22, the Reubenites, Gadites, and half-tribe of Manasseh built an altar as a witness, not for sacrifices, but to demonstrate their unity in worship with the other tribes of Israel. This altar was a reminder to future generations that they were all one nation under God, despite the physical separation of the Jordan River. The act sparked concern among the other tribes, fearing idolatry, but was clarified by the eastern tribes to be a memorial rather than a place of false worship.