From the time of creation, the earth was filled with trepidation, for “God made a condition with the works of creation, saying: ‘If the Jews accept the Torah, you will endure; if not, I will return you to primordial chaos’” (Shabbat 88a). This idea is also expressed in a midrash on the verse “And God saw all that He had made, and found it very good. And there was evening and there was morning, the sixth day” (Bereishit 1:31). According to this midrash, the definite article “the” is prefixed to “sixth day” to teach us that the existence of the world depends upon a specific sixth day – the sixth day of Sivan, when the Jews arrived at Mount Sinai and accepted the Torah.
Actually, we were given the Torah on the fifty-first day of Sefirat Ha-omer. According to the Gemara, God originally commanded Moshe to tell the Jews to purify themselves for two days before the giving of the Torah on Friday. Moshe added a day, instructing the Jews to purify themselves for three days. God went along with Moshe and waited until Shabbat to reveal Himself on Mount Sinai (Shabbat 86b-87a). This remarkable account teaches us how important the Oral Torah is. It mediates between us and the exalted Written Torah; without the Oral Torah, the Written Torah could not have been revealed. Therefore, even the giving of the Torah itself was postponed for a day because of the Oral Torah, that is, the interpretation of Moshe Rabbeinu.
However, this would seem to present us with a difficulty. As Shulḥan Arukh (494:1) states, we refer to Shavu’ot as “Zeman matan Torateinu” (the season of the giving of our Torah). Why do we call it that if Shavu’ot is not actually the day the Torah was given? Shavu’ot takes place on the fiftieth day of the omer, while the Gemara above states that we received the Torah on the fifty-first day! The answer is that in truth, from the heavenly point of view, right after the completion of Sefirat Ha-omer the sacred day of the giving of the Torah arrived, and God blessed us with the Torah (in potential). It was only from the human point of view that we needed an additional day before we were capable of receiving it (in actuality). Nevertheless, for future generations, the giving of the Torah is commemorated on the day that God had originally ordained and sanctified, when the Torah was given to us in potentiality (Maharal, Tiferet Yisrael ch. 27).[1]