Joshua 4:23
For the LORD your God dried up the waters of Jordan from before you, until ye were passed over, as the LORD your God did to the Red sea, which he dried up from before us, until we were gone over: For the LORD your God dried up the waters of Jordan from before you, until ye were passed over, as the LORD your God did to the Red sea, which he dried up from before us, until we were gone over:
God dried up the waters of the Jordan from before Israel until they were passed over. He did this just as He had dried up the Red Sea from before the earlier generation, their ancestors. By drying the Jordan He enabled Israel to cross on dry ground, repeating the kind of miracle performed at the Red Sea. The crossing was a witness to His mighty power and a deliverance.
The stones taken from the riverbed and set up at Gilgal preserved the crossing as a reminder. The account preserves God's dealings with Israel as a lesson to be studied and remembered by later generations, so that the teachings of His Word remain instructive and impressive. The deliverance was to be remembered and told to future generations, so that all would know the Lord's power and Israel would reverence Him. Parents were to recount God's act to their children to impress its history on later generations.