The Oral Torah comprises the Mishnah, the Gemara, and the Midrash. The original name of the Zohar is Midrash Yehi Or, “Let there be light.”
According to teaching of the Ba’al Shem Tov, learning Mishnah corresponds to submission, Gemara to separation, and Midrash to sweetening.
Mishnah Gemara Midrash = 1183 = 7 times 13 squared. “Torah and Havayah are one.” Torah Havayah = 637 = 13 times 7 squared.
637 and 1183 = 1820 = 70 times 26, mystery times Havayah, as in the verse “The mystery of Havayah is revealed to those that fear Him.”
“Fear of God [Havayah]” also = 637 (13 times 7 squared). God’s essential Name Havayah appears 1820 times in the Torah (Five Books of Moses).