En route to the promised land, Joshua led the Israelites to the shores of the River Jordan.  How were they going to cross it?  God calmed Joshua, assuring him that by this wonder He would do, He was going to exalt him.  Joshua then instructed the people to consecrate themselves, stay pure because tomorrow God will do wonders among them.  He thereafter instructed the Priests to carry the Ark of the Covenant ahead of them; as soon as their feet touched the water, it would divide, making a heap and so the people crossed over on dry ground.

After they had crossed over, Joshua asked twelve men to pick big rocks from the middle of the Jordan and to stack them as a Memorial at the other end.  Why?  So that when their children would ask what it meant, they would tell them how God miraculously made a way for them to cross over the Jordan.  And as promised, God used this event to exalt Joshua in the sight of all Israel, and they feared him just as they feared Moses.  Of course, the Priests came out and the waters returned back.  Then Joshua instructed them to tell their children about these wonders that God had done, so that the whole world might know that God’s hand is mighty.