Joshua 22:1-34
This passage contains my favorite event in Joshua.  The previous chapter ended with the statement, "And the LORD gave them rest on every side just as he had sworn to their fathers.  Not one of all their enemies had withstood them...Not one word of all the good promises that the LORD had made in the house of Israel had failed; all came to pass." 
After approximately five years of war, peace had come to the Israelites in the Promised Land.  It was time for the warriors of Ruben, Gad and the half-tribe of Manasseh to return to their homes on the eastern side of the Jordan.  What a faithful group of 40,000 men (Joshua 4:13).  They had kept their commitment to Moses and Joshua to fight alongside their brothers until they took possession of the land.  After Joshua had commended them for their service, he reminded them to carefully obey God's law by loving Him with all their heart and soul.
Before crossing the Jordan on their way home, the men built a large altar resembling the one at Shiloh.  When the other tribes heard, they prepared for war because they thought the altar was to be used for sacrifices instead of the one in Shiloh.  Deuteronomy 12:11-14 instructs the people to only offer sacrifices in the place God chose to make his name dwell. 
Before going to war, a delegation, led by Phinehas, was sent to question the reason for the new altar.  This action was obedience to God's commands.  Deuteronomy 13:12-15 provided instruction when word came that a city of the Israelites turned to serve other gods.  God told them to determine the truth of the situation by inquiring, searching and asking diligently for the truth.  If the city had, in fact, turned to other gods, everything associated with this town was to be devoted to destruction. 
Can you think of a better person than Phinehas to lead this group?  Don't you know his presence proved the commitment and determination to obey God's commands given in Deuteronomy 13?  If you don't remember Phinehas, read Numbers 25:1-13.  God commended him for being as zealous for the name of the LORD as the LORD was.  This passage of Scripture will also clarify the reference to Peor in verses 17-18.  The nation of Israel had definitely learned the lesson of Achan.
When the people on the eastern side of the Jordan heard the accusation, they cried out to the Mighty One, God, the LORD to make known their intent in building the altar.  The reason for the altar was not for sacrifices but remembrance.  It was to be a witness for the nation of Israel on both sides of the Jordan of the faithfulness of God, so the nation would always be united in the worship of the True God.  They were committed to the proper worship of the LORD in Shiloh, even though it would require them to travel a great distance.  This altar was never intended to replace the LORD's altar. 
It is easy for me to remember how quickly the nation of Israel turned to other gods, but this event commends the people for their faithfulness to the LORD.  Everyone involved was obedient to the LORD, but because of a misunderstanding, a fight between them nearly occurred. 
Their example is a good one for us to remember.  How easy it is to hear something and base our action on hearsay rather than diligently searching for the truth before responding.  Many conflicts within the church could be avoided if this example were followed. 
It is proper to establish markers in our lives that we can look back on as a reminder of God's faithfulness and our commitment to Him.  We will see Joshua build another witness for the people in Joshua 24:27. 
Thankfully, the LORD always leaves a "Witness."  We have the witness of His creation, His Son, His Church and His Word. 
Mighty One, God, the LORD, You are the One who is faithful.  You have left multiple witnesses of Yourself.  Teach us, Your children, to be faithful witnesses.  Thank You for this example of Your people obediently following Your instruction.