וַיִּכְתֹּ֨ב עַֽל־הַלֻּחֹ֜ת כַּמִּכְתָּ֣ב הָרִאשׁ֗וֹן אֵ֚ת עֲשֶׂ֣רֶת הַדְּבָרִ֔ים אֲשֶׁ֣ר דִּבֶּר֩ יְהוָ֨ה אֲלֵיכֶ֥ם בָּהָ֛ר מִתּ֥וֹךְ הָאֵ֖שׁ בְּי֣וֹם הַקָּהָ֑ל וַיִּתְּנֵ֥ם יְהוָ֖ה אֵלָֽי׃
И он написал на столах, согласно первому письму, десять слов, которые Господь сказал вам на горе среди огня в день собрания; и Господь дал их мне.
Haamek Davar
Hashem addressed you. Later (Devarim 10:4) with regard to the first set of Ten Commandments, which says, “Remember the day of Shabbos” the verse states, “That Hashem addressed to you,” whereas with regard to the second tablets which say “Preserve the day of Shabbos,” (Devarim 5:12) it states, “that Hashem addressed you.” This is because all of Yisroel heard “Remember” but only Moshe heard “Preserve” and the rest of Yisroel did not. They heard other sounds apart from the words that they heard. The amazing fact that Moshe is describing here, “Hashem addressed you” meaning that you heard the sounds of speech but not words.
Rashbam
ויכתוב על הלוחות, G’d Himself inscribed the Tablets. The same words as had been inscribed on the first Tablets were inscribed on the second set. (as per verse 1 of our chapter) The same information is repeated by Moses in Deuteronomy 10,4
Malbim
He remained there with Ad-noy. Moshe’s body ascended in spirituality until it was capable of surviving on the food of the soul. Thus according to Shemos Rabbah (48) he was nourished by the splendor of the Shechinah. The Ten [Commandments]. The first tablets were inscribed on both sides, containing all the laws of the Torah in all their details, both exoteric and esoteric. The second tablets, by contrast, contained only the Ten Commandments.