Midrash su Deuteronomio 32:9

The Holy One, blessed be He, however, befriended Israel and called them his possessions, inheritance, (and) portion, as it is said: For the portion of the Lord is His people Jacob, the lot of His inheritance (Deut. 32:9); and ye shall be Mine own treasure among all the peoples (Exod. 19:5); and I have planted thee a noble vine, wholly a right seed (Jer. 2:21). Why did the Holy One, blessed be He, concern Himself from the very beginning of time with the genealogies of the nations? This may be likened to a king who dropped a pearl into sand and pebbles. The king was compelled to search the sand and the pebbles to recover the pearl. As soon as he recovered the pearl, however, he discarded the sand and the pebbles, for he was only interested in retrieving the pearl.

One time I was walking on the way. A man found me, and went with me on the way of mitzvot, and he had mikra (ie: written law) but no mishnah (ie: oral law). And he said to me, "Rabbi, mikra was given to us from Mount Sinai. Mishnah was not given to us from Mount Sinai." And I said to him, "My son, mikra and mishnah were both of them said from the mouth of God." And what is the difference between mikra and mishnah? Rather he told him a parable: To what is this matter similar? To a human king (lit: a king of flesh and blood) who had two servants, and he loved them with a great love. And he gave to one a kab (a measure) of wheat and to the other kab of wheat. And he also gave to each one of them a bundle of flax. The wise one of them took the flax and wove a beautiful cloth, and took the wheat and made it into fine flour, and sifted it, and ground it, and kneaded it, and baked it, and set it on the table, and spread the beautiful cloth over it, and left it there until the king should come. And the fool of them did nothing. After some time the king came into his house, and said to them, to his two servants, "My sons, bring to me what I gave you." One of them brought out the bread of fine flour, on the table, with the beautiful cloth spread over it. And the other of them brought out the wheat in a pile and the bundle of flax upon it. Woe for that shame! Woe for that disgrace! Which one is more favored? You must admit it is the one who brought out the bread on the table with the beautiful cloth spread over it.

These are the generations of Noah. Blessed be the name of the King of Kings, the Holy One, blessed be He, who chose Israel from among the seventy nations of the world, as it is written: For the portion of the Lord is His people Jacob, the lot of his inheritance (Deut. 32:9). He gave us the Written Law (the Five Books of Moses), which contains hidden and obscure teachings, and explained them in the Oral Law (codified in the Mishnah), which was revealed to Israel alone. What is more, the Written Law enunciates only the general principles of the law, while the Oral Law discusses the specifics of the law. The Written Law is brief, while the Oral Law is lengthy, as it is written: The measure thereof is longer than the earth and broader than the sea (Job 11:9).