וְאֵת֩ שְׁתֵּ֨ים עֶשְׂרֵ֤ה הָֽאֲבָנִים֙ הָאֵ֔לֶּה אֲשֶׁ֥ר לָקְח֖וּ מִן־הַיַּרְדֵּ֑ן הֵקִ֥ים יְהוֹשֻׁ֖עַ בַּגִּלְגָּֽל׃
And those twelve stones, which they took out of the Jordan, did Joshua set up in Gilgal.
Read halakhic rulings (Jewish law) on Joshua 4:20: and classical halakhic sources.