Midrash su Ester 10:3

“There was a Judean man in the Shushan citadel, and his name was Mordekhai, son of Ya'ir, son of Shimi, son of Kish, a Benjamite” (Esther 2:5).
“There was a Judean man [ish] in the Shushan citadel” – ish teaches that Mordekhai, in his generation, was the equivalent of Moses, in his generation, as it is written about him: “And the man [veha’ish] Moses was very humble” (Numbers 12:3). Just as Moses stood in the breach, as it is written: “He said He would destroy them, were it not for Moses His chosen one, who stood before Him in the breach…” (Psalms 106:23); also Mordekhai did likewise: “A seeker of good for his people and spokesman of peace for all his descendants” (Esther 10:3).
Just as Moses taught Torah to Israel, as it is written: “See, I have taught you statutes and ordinances” (Deuteronomy 4:5), also Mordekhai did so, as it is written: “Matters of peace and truth” (Esther 9:30), and as it is written: “Acquire truth and do not sell” (Proverbs 23:23).
“And his name was Mordekhai” (Esther 2:5) – the wicked precede their names: “Naval was his name” (I Samuel 25:25); “Sheva ben Bikhri was his name” (II Samuel 20:21). However, the righteous, their names precede them: “And his name was Manoaḥ” (Judges 13:2); “And his name was Kish” (I Samuel 9:1); “And his name was Elkana” (I Samuel 1:1); “And his name was Boaz” (Ruth 2:1); “And his name was Mordekhai.” It is because they are similar to their Creator, as it is written: “But by My name, the Lord, I was not known by them” (Exodus 6:3).
“Judean” – why was he called Judean? Was he not a Benjaminite?⁶Mordekhai is identified as coming from the tribe of Benjamin in Esther 2:5. It is because he unified the name of the Holy One blessed be He⁷Actions which assert that there is only one God are referred to as “unifying the name.” before all creatures; that is what is written: “[And Mordekhai] would not bow and would not prostrate himself” (Esther 3:2). Was he contrary and violating the king’s decree? Rather, when Aḥashverosh commanded [everyone] to prostrate themselves to Haman, he [Haman] carved an idol [and set it] over his heart, intending that they prostrate themselves to the idol.
When Haman saw that Mordekhai would not prostrate himself to him, he was filled with fury. Mordekhai said to him: ‘There is a Master who exalts over all the exalted; how can I forsake him and prostrate myself to an idol?’ Because he unified the name of the Holy One blessed be He, he is called Judean [Yehudi], meaning by himself [yeḥidi].⁸Just as God is only one [yeḥidi] so was Mordekhai called yeḥidi.
Some say that he was the equivalent of Abraham in his generation. Just as Abraham allowed himself to be put into the fiery furnace and went about causing people to acknowledge the greatness of the Holy One blessed be He – that is what is written: “And the souls they had gotten in Ḥaran” (Genesis 12:5), so too, Mordekhai, in his time, people acknowledged the greatness of the Holy One blessed be He. That is what is written: “Many of the peoples of the land became Jews, as the fear of the Jews had fallen upon them” (Esther 8:17). He unified the name of the Holy One blessed be He, and sanctified it. Therefore, he is called yehudi, as it is written: “A Judean [yehudi] man” – don’t read it as yehudi, but rather, as yeḥidi.

“On each day, Mordekhai would walk before the courtyard of the harem, to find out how Esther was, and what would be done with her” (Esther 2:11).
“On each day, Mordekhai would walk before the courtyard of the harem” – [to give her the opportunity] to ask about her blood stains and her menstrual status.¹⁵According to the midrash, Mordekhai was the head of the Sanhedrin and Esther would ask him halakhic questions about her status as a menstruant. “To find out how Esther was” – that they should not cast any spells of sorcery upon her. Rabbi Yaakov bar Aḥa said: The Holy One blessed be He said to him: You sought to ascertain the wellbeing of one person – “to find out how Esther was”; by your life, ultimately you will seek to ascertain the wellbeing of an entire nation. That is what is written: “Seeking good for his people and speaking of peace for all his descendants” (Esther 10:3).

“And Mordekhai went out from before the king in royal dress of blue and white wool, and a great gold crown, and a robe of fine linen and purple. The city of Shushan reveled and rejoiced” (Esther 8:15).
“And Mordekhai went out from before the king in royal dress…” Rabbi Pinḥas says: Mordekhai reigned over the Jews. Just as the king wears purple, so did Mordekhai wear purple. Just as the king sets a great crown on his head, so did Mordekhai wear “a great gold crown” (Esther 8:15). Just as fear of the king is over the whole land, so was fear of Mordekhai over all of them, as it says: “For fear of Mordekhai had fallen upon them” (Esther 9:3). Just as the king’s coin is accepted in the entire land, so was Mordekhai’s coin accepted. And what was his coin? Mordekhai on one side and Esther on the other. Why? Because he was a good man and a peaceful man and sought peace, as it says: “For Mordekhai the Jew…[a seeker of good for his people and a spokesman of peace for all his descendants] (Esther 10:3). About him scripture says: “Mark the man of integrity and behold the upright one, for there is a future for the man of peace” (Psalms 37:37).