וְצַוּ֣וּ אוֹתָם֮ לֵאמֹר֒ שְׂאֽוּ־לָכֶ֨ם מִזֶּ֜ה מִתּ֣וֹךְ הַיַּרְדֵּ֗ן מִמַּצַּב֙ רַגְלֵ֣י הַכֹּהֲנִ֔ים הָכִ֖ין שְׁתֵּים־עֶשְׂרֵ֣ה אֲבָנִ֑ים וְהַעֲבַרְתֶּ֤ם אוֹתָם֙ עִמָּכֶ֔ם וְהִנַּחְתֶּ֣ם אוֹתָ֔ם בַּמָּל֕וֹן אֲשֶׁר־תָּלִ֥ינוּ ב֖וֹ הַלָּֽיְלָה׃ (ס)
Y mandadles, diciendo: Tomaos de aquí del medio del Jordán, del lugar donde están firmes los pies de los sacerdotes, doce piedras, las cuales pasaréis con vosotros, y las asentaréis en el alojamiento donde habéis de tener la noche.
Tosefta Sotah
When they were still in the Jordan, Joshua said to them, "For this purpose are you crossing to the Land: That you will dispossess its inhabitants, as it is said (Num. 33:52), 'And you shall dispossess all the inhabitants of the Land before you, and destroy them, etc.' And if you do not dispossess them (Num. 33:56), 'it shall be that as I planned to do to them, I will do to you.' And if you do not accept [this commandment], the waters will come and wash over you." When they were still in the Jordan, Joshua said to them, "And each man among you shall lift one stone onto your shoulders, corresponding to the number of tribes of the Children of Israel" (Josh. 4:5), "And you shall rest them, etc." (Josh. 4:3), "beneath the spot where the priests' feet [had stood]" (Josh. 4:9), as a sign for the children that their forefathers had crossed through the Jordan. When they were still in the Jordan, Joshua said to them (Josh. 4:3), "Pick up twelve stones for yourselves from here, within the Jordan, from beneath the spot where the priests' feet [had stood]." Rabbi Yehuda says, Rabbi Chalafta and Elazar ben Matya and Chananiah ben Chachinai (alt., "Chinai" (see Lieberman)) stood on the same stones, and weighed each and every one, [and found that] they each had a weight of forty seahs. From here you can estimate how much the grapes [taken back by the spies] weighed. And as soon as the last one who was among the Israelites ascended from the Jordan, the waters of the Jordan returned to their place, as it is said (Josh. 4:18), "And the waters of the Jordan returned to their place, and they flowed like previous day and the day before that, over the entire riverbed." It turns out that Israel was on one side, and the Ark and its bearers were on one side, the Ark was carried by its bearers, and they brought it across the Jordan.
Tosefta Sotah
It comes out that you can say there were three sets of stones: One that Moses erected on the banks of the Jordan River on the Plains of Moab (Deut. 27:2), and one that was under the feet of the priests [in the middle of the Jordan] (Josh. 4:3), and one that they brought over with them (Josh. 4:5).