Joshua understood how important this was. In Joshua 4 we see where the entire Nation of Israel had just crossed the Jordan river, at the height of flood season, on dry land, because God parted the waters, much like He parted the Red Sea when their ancestors left Egypt. Joshua didn't want future generations to forget what God did, so he had a leader from each tribe, pick up and bring a large stone from the bottom of the Jordan River to the shore of the Promised Land. In Joshua 4:5-7 we see the reason for this . . .
"Go over before the ark of the Lord your God into the middle of the Jordan. Each of you is to take up a stone on his shoulder, according to the number of the tribes of the Israelites, to serve as a sign among you. In the future, when your children ask you, ‘What do these stones mean?’ tell them that the flow of the Jordan was cut off before the ark of the covenant of the Lord. When it crossed the Jordan, the waters of the Jordan were cut off. These stones are to be a memorial to the people of Israel forever."
This is why the Legacy Coalition exists - to help churches help grandparents know how to pass on a legacy of faith and to encourage and equip grandparents to do this as well. You'll learn more about the Legacy Coalition at this link.