Joshua 4:7 WEB

⁵  and Joshua said to them, Pass over before the ark of Yahweh your God into the midst of the Jordan, and take up every man of you a stone on his shoulder, according to the number of the tribes of the children of Israel;

⁶  that this may be a sign among you, that when your children ask in time to come, saying, What do you mean by these stones?

⁷  then you shall tell them, Because the waters of the Jordan were cut off before the ark of the covenant of Yahweh; when it passed over the Jordan, the waters of the Jordan were cut off: and these stones shall be for a memorial to the children of Israel forever.

⁸  The children of Israel did so as Joshua commanded, and took up twelve stones out of the midst of the Jordan, as Yahweh spoke to Joshua, according to the number of the tribes of the children of Israel; and they carried them over with them to the place where they lodged, and laid them down there.

⁹  Joshua set up twelve stones in the midst of the Jordan, in the place where the feet of the priests who bore the ark of the covenant stood: and they are there to this day.