Talmud Beitzah 25b

It is taught in a baraita in the name of Rabbi Meir: For what reason was the Torah given to the Jewish people? It is because they are impudent, and Torah study will weaken and humble them. A Sage of the school of Rabbi Yishmael taught the following with regard to the verse: “From His right hand went a fiery law for them” (Deuteronomy 33:2); The Holy One, Blessed be He, said: Based on their nature and character, these people, the Jews, are fit to be given a fiery law, a hard and scorching faith. Some say a different version of this baraita: The ways and nature of these people, the Jews, are like fire, as, were it not for the fact that the Torah was given to the Jewish people, whose study and observance restrains them, no nation or tongue could withstand them.