出エジプト記 19:11

והיו נכנים AND LET THEM BE PREPARED — separated from their wives (Mekhilta; cf. Rashi on Shabbat 87a). ליום השלישי AGAINST THE THIRD DAY, which is the sixth of the month. On the fifth Moses built the altar under the mountain and the twelve monuments — the whole narrative as is stated later on in the Sidra ואלה המשפטים (Exodus 24:4), for there is neither “earlier” nor “later” (there is no chronological order) in the Torah (Mekhilta-2). לעיני כל העם BEFORE THE EYES (in the sight) OF ALL THE PEOPLE — This tells us that there was not a blind person amongst them — that they had all been healed of their blindness (Mekhilta).

and be ready by the third day: for on the third day the Lord will come down in the sight of all the people upon mount Sinay.

וְהָי֥וּ נְכֹנִ֖ים לַיּ֣וֹם הַשְּׁלִישִׁ֑י כִּ֣י ׀ בַּיּ֣וֹם הַשְּׁלִשִׁ֗י יֵרֵ֧ד יְהֹוָ֛ה לְעֵינֵ֥י כׇל־הָעָ֖ם עַל־הַ֥ר סִינָֽי׃