Midrash su Levitico 23:44

(Fol. 32) R. Shephatia said again in the name of R. Jochanan: "Whence do we know that we may avail ourselves of a Heavenly voice? It is said (Is. 30, 31) Thine ears shall hear a thing from behind them, saying. When is this true? When one perceives a male voice in town, and a female voice in the country, and also when it says: 'Yea, yea,' or 'Nay, nay' [in double]." Another thing said R. Shephatia in the name of R. Jochanan: "Whoever reads without sweetness, and chants while reading Talmudic lessons, of him says the verse (Ezek. 20, 25) And I also have given unto them laws that are not good and ordinances whereby they could not live." R. Mesharshia raised the following objection: "Shall I say because one cannot sweeten his voice, ordinances whereby they could not live should be applied to him?" Therefore we must say that it refers to what R. Mesharshia said: "If two scholars are in one town, and derive no pleasure in discussing Halacha, to the passage. And ordinances whereby they could not live is applied."

(Lev. 23, 44) And Moses spoke of the festivals of the Lord to the children of Israel; i.e., he told them the merit of reading the portions of the Torah each in its season. Our Rabbis were taught: Moses ordered Israel to discuss and lecture on the subject of the day; the Halachas of Passover on Passover, the Halachas of Pentecost on Pentecost, and the Halachas of Tabernacles on the Feast of Tabernacles.

12) (Vayikra 23:44) "And Moses declared the festivals of the L–rd to the children of Israel": We re hereby apprised that Moses related to Israel the laws of Pesach on Pesach, the laws of Shavuoth on Shavuoth, and the laws of Succoth on Succoth. In the language that he heard it (from the L–rd), he related it to Israel, (after which he imparted to them the oral law upon it. And all of the sections of the Torah were related in the same manner. R. Yossi Haglili says: The festivals of the L–rd were declared, but not the Sabbath of creation along with them. Ben Azzai says: The festivals of the L–rd were stated, but not the section of vows along with them.