וְכָתַבְתָּ֣ עַל־הָאֲבָנִ֗ים אֶֽת־כָּל־דִּבְרֵ֛י הַתּוֹרָ֥ה הַזֹּ֖את בַּאֵ֥ר הֵיטֵֽב׃ (ס)
你要把這律法的一切話清清楚楚地寫在這些石頭上。」
Rashi
באר היטב EXPLAINING THEM WELL — i.e. in seventy languages (Sotah 32a; cf. Rashi on Deuteronomy 1:5).
Rashbam
'וכתבת על האבנים את כל דברי וגו, for when they were now sworn at Mount Gerizim and Mount Eyval the Torah was present before them in written format, and they were sworn to keep its commandments.