Joshua 22:
"And the children of Reuben and the children of Gad called the altar Ed: for it shall be a witness between us that the LORD is God." ~Joshua 22:34
So Joshua calls the Reubenites, and the Gadites, and the half tribe of Manasseh to him, and commends them for fulfilling their vow to fight with their brethren as they possessed the land of their inheritance, and he admonished them to keep the laws of God and to love God with all that is in them, and he blessed them, and sent them back to their own land that Moses had given them, on the other side of the Jordan.
When they reached the other side of the Jordan, they built a HUGE altar that nearly caused a war with their brethren on the other side of the Jordan, because they found it offensive. Phinehas the son of Eleazar the priest, and ten princes came to ask why they had committed such a trespass. They answered them, saying that they did not build the altar for burnt offering, nor for sacrifice, but as a memorial that they are still very much a part of their brethren on the other side of the Jordan.
Phinehas the son of Eleazar the priest and the ten princes were pleased to hear this. And Phinehas the son of Eleazar the priest said unto the children of Reuben, and to the children of Gad, and to the children of Manasseh, This day we perceive that the LORD
is among us, because ye have not committed this trespass against the LORD: now ye have delivered the children of Israel out of the hand of the LORD.
So there was no war, but peace reigned.