Midrasz do Ezdrasza 2:2

Words of peace and truth. R. Tanchum, and according to others, R. Ashi, said: "We may infer from this that it should be written similarly to real words of the Torah; written on ruled parchment.]" And the order of Esther confirmed this Purim. Is it only the words of Esther and not the fasting and prayers? R. Jochanan said: "Read together the former verse with this: The matters of the fastings, the prayers, and the order of Esther confirmed this Purim." (Ib.) For Mordecai the Jew was second in rani after the king Ahasuerus, and great among the Jews, and acceptable to the multitude of his brethren. R. Joseph was taught: To the multitude, but not to all? From this we infer that a part of the Sanhedrin turned away from him. R. Joseph said: "The study of the Law is greater than the saving of lives, for before [becoming popular with Ahasuerus] Mordecai was mentioned the fifth, but later the sixth. Before he was mentioned the fifth, as it is written (Ez, 2, 2) Who came with Zerubbabel, Jeshua, Nehemiah, Serayah, Roalyah, Mordecai, Balsha; and later it is written (Neh. 7, 7) Who came with Jeshua, Nehemiah, Azaryah, Raamath, Nachmeini, Mordecai and Balshan."

Rabbi Simeon said: Come and see the wisdom of Mordecai, for he knew seventy languages, as it is said, "Which came with Zerubbabel, Jeshua… Mordecai, Bilshan" (Ezra 2:2), and he sat in the gates of the king to see that Esther and her maidens should not become defiled by any kind of unclean food. He heard the two eunuchs of the king speaking in the language of the Chaldees, saying: Now will the king take the afternoon sleep, and when he arises he will say, Give me a little water; let a deadly poison be given to him in the golden vessel, and he will drink thereof and die. Mordecai went in and told Esther. Now Esther told the king in the name of Mordecai, as it is said, "And Esther told the king in Mordecai's name" (Esth. 2:22). Hence (the Wise Men) have said: Whosoever tells a matter in the name of its author brings redemption into the world.