One of the Sages said to Rav Kahana: Did you hear what is the reason that the mountain was called Mount Sinai? Rav Kahana said to him: It is because it is a mountain upon which miracles [nissim] were performed for the Jewish people. The Sage said to him: If so, it should have been called Mount Nisai, the mountain of miracles. Rather, Rav Kahana said to him: It is a mountain that was a good omen [siman] for the Jewish people. The Sage said to him: If so, it should have been called Har Simanai, the mountain of omens. Rav Kahana said to him: What is the reason that you do not frequent the school where you can study before Rav Pappa and Rav Huna, son of Rav Yehoshua, who study aggada? As Rav Ḥisda and Rabba, son of Rav Huna, both said: What is the reason it is called Mount Sinai? It is because it is a mountain upon which hatred [sina] for the nations of the world descended because they did not accept the Torah.
Some commentaries explain that the nations of the world began hating the Jewish people when the Torah was given at Sinai. A different version of this statement, which appears in some collections of the midrash, supports this explanation. From the moment they received the Torah, the Jewish people became isolated. Still, most sources explain this differently, as indicating that hatred descended among the nations of the world. The revelation at Sinai introduced compulsory faith to the world, as well as the concept of a correct and incorrect way to serve God. This became a bone of contention between the nations of the world.