Mishneh Torah, Laws of Virtues, 2:6, Maimonides
It is forbidden for a person to speak in smooth speech and flattery. He ought not be one thing in mouth and another thing in heart. Rather, his inside ought be like his outside—what is in his heart ought be in his mouth. It is forbidden to deceive (literally steal the mind of) another human being. Even the mind of an idolator. For instance: a person should not sell an idolator a piece of meet that has died a natural death, as if it were a ritually slaughtered animal. Nor should one sell a shoe, the leather of which came from the hide of a beast that has died naturally allowing it to be believed as if it were a ritually slaughtered animal. One must not invite another to a meal when one is aware that the person will not accept the invitation. Nor should one display signs of friendship which he knows will not be accepted. So too one should not open casks of wine for a guest which must be opened for sales in any case as if you are opening them in his honor. Even a single word of flattery or ‘mind stealing” is forbidden. A person should always cherish truthful speech, an honest spirit, and pure heart.
Netivot Olam (The Path of a Good Name), The Maharal of Prague (Yehuda Lowe)
A good name is elevated above other virtues because it defines the stature of the person himself. For the name refers to all that concerns the essence of a person. Not like wealth, or wisdom, or the other virtues, but his very being… A good name endures and lives after the physical death of a person.
Mishneh Torah, Laws of the Sanhedrin, 2:7, Maimonides
...it is essential that every one of the members of a court of three possess the following seven qualifications: wisdom, humility, awe of God, hate of greed, love of truth, love of his fellow men, and a good name.
Avot d’Rebbe Natan, Chapter 12
“Be among the students of Aaron: He loved peace; he pursued peace; he loved people, and brought them close to Torah.” Rebbe Natan: “Loved peace”. How? It teaches: A person ought love peace in Israel between each and every person just as Aaron loved peace between each and every person, as it states: the Torah of truth was on his mouth and perversity was never on his lips, and he brought back many from iniquity (Malachi 2:6)…
And likewise, when two people would get into a bitter argument, Aaron would come along afterwards and say to one of them: “My son, see what your friend said: he’s tearing his heart out and rending his clothes, saying: “Woe is me! How will I be able to look at my friend. I am ashamed of myself for hurting him! Aaron would sit with him until he removed the anger from his heart. And then Aa-ron would go to the other friend, and say to him: My son, see what your friend is doing: he’s tearing his heart out, ending his clothes, and saying, woe is me, how can I see my friend again. I am ashamed of myself since I hurt him. Aaron would sit with him until he removed the passion from his heart.
Babylonian Talmud, Ketubot 16b-17a
How does one dance before the bride [i.e. what does one say about her]? Beit Shammai says: “The bride is as she is.” Beit Hillel says: “The bride is beautiful and graceful.” Beit Shammai said to Beit Hillel: “If the bride is lame or blind, will we say she is beautiful and graceful? Did the Torah not say, ‘Keep distant from falsehood’ (Shemot 23:7)?” Beit Hillel said to Beit Shamai: “Even according to your position, if a person acquires a poor purchase in the market, should you praise it in his eyes or denigrate it? You should praise it.” Therefore, the Sages said: “A person’s disposition should always be pleasant with people.”
Nachmanides' Commentary on Deuteronomy 6:18
Our rabbis have a midrash on this verse: They have said; “That which is right and good refers to a compromise and going beyond the letter of the law. (Baba Kama 101a) The intent of this is as follows: At first Moses stated that you are to keep His statutes and testimonies which he commanded you, and now he is stating that that even where He has not commanded you, give thought, as well to do what is good and right in His eyes, for he loves the good and the right.