Joshua 4:9
And Joshua set up twelve stones in the midst of Jordan, in the place where the feet of the priests which bare the ark of the covenant stood: and they are there unto this day. And Joshua set up twelve stones in the midst of Jordan, in the place where the feet of the priests which bare the ark of the covenant stood: and they are there unto this day.
Joshua set up twelve stones in the midst of the Jordan, taken from the riverbed, in the very place where the feet of the priests bearing the ark of the covenant stood while the people crossed over. The twelve-stone memorial is also recalled as set up at Gilgal to commemorate the crossing. The twelve stones stand for Israel's twelve tribes, one stone for each tribe.
The setting is Israel's miraculous passage through the Jordan on dry ground into the promised land. The memorial was set up by divine direction. The stones remained there as a lasting memorial and witness to the miracle, as expressed by the phrase unto this day.
The stones mark the covenant the Lord made with Israel as they crossed the Jordan into the promised land. The stones were meant to preserve the memory of God's deliverance and mighty power, prompting the people to tell the history to their children and grandchildren through successive generations, so that all peoples might know His power and Israel would revere Him always. Gilgal, associated with the memorial, was Israel's first encampment in the promised land and a place marked by important events in the nation's history. Elijah's rebuilding of the altar with twelve stones was a reminder of and showed respect for Israel's covenant with God recalled by the Jordan stones.