Musar su Salmi 76:78

Creation i.e. בריאה, is divided into three "days." On the first "day," G–d created; on the second "day," He ensured that what He had created would endure. This was the day on which the Torah was given to the Jewish people, when the earth was both frightened and reassured in turn. G–d had added the letter ה to the Torah's report that "it was evening it was morning יום הששי, "the sixth day." [an allusion to Israel having to accept the Torah so that earth's continued existence would be assured based on Midrashim we quoted elsewhere. Ed.] יום הששי, "The sixth day," refers to the 6th of Sivan, the date on which the Jewish people accepted the Torah. G–d had threatened that non-acceptance would result in the world again being turned into Tohu (compare Shabbat 88). The third "day" of creation is the day when G–d's handiwork will undergo a complete rejuvenation in the messianic future, seeing that G–d's original handiwork had been largely ruined through Adam's sin (and that of his descendants). At that time the verse ישמח ה' במעשיו, "G–d will rejoice in His works," will be fulfilled (Psalms 104,31, the word ישמח having the same letters as the word משיח).