Why the Oral Torah Seals the Covenant at Sinai

"And the LORD said to Moses: Write for yourself" (Exodus 34:27) — these are the Ten Commandments. "the" [et] — to include the rest of the commandments. "these words" — this is the entire book of the Torah. "For according to these words" — these are the rulings of the Talmud, for the essence of the covenant was cut over the interpretations of the Torah, as it is said, "and teach it to the children of Israel, put it in their mouths" (Deuteronomy 31:19). For anyone who expounds a verse according to its plain form, without midrash and without the thirteen principles by which the Torah is expounded, of him Scripture says, "and the fool walks in darkness" (Ecclesiastes 2:14).