Gemara

Bunyas' son came in front of Rebbi. Rebbi commanded 'clear a [dignified] place for a millionaire';

Ploni came in front of Rebbi. Rebbi commanded 'clear a [more dignified] place for a multimillionaire.'

R. Yishmael b'Rebbi Yosi: Bunyas owns 1000 ships on the sea and 1000 cities! (Surely his son is richer than Ploni.)

Rebbi: Tell Bunyas to give to his son clothes appropriate for his [awesome] wealth.

Rebbi and R. Akiva used to honor rich people.

(Rava bar Mari): "Yeshev Olam... Chesed v'Emes Man Yintzeruhu" - the world is settled when there is Chesed and truth.

Shabbos 153b (R. Yitzchak): Chachamim had another Heter [to bring a wallet home on Shabbos, i.e. carrying it less than four Amos at a time], but they didn't want to reveal it.

This is because "Kevod Elokim Hester Davar u'Chvod Melachim Chakor Davar."

Sanhedrin 6b (Beraisa - R. Yehoshua ben Korchah): If a Talmid in front of his Rebbi sees Zechus (merit) for the Oni (poor person) and Chov (liability) for the Ashir [and his Rebbi is about to rule in favor of the Ashir], he may not be silent - "Lo Saguru Mipnei Ish";

R. Chanin says, do not withhold your words due to a person's honor.

Shevu'os 31a (Beraisa): "Mi'Devar Sheker Tirchak" teaches that if a Talmid in front of his Rebbi sees Zechus for the Oni and Chov for the Ashir, he may not be silent.

Rishonim

Rambam (Hilchos Sanhedrin 22:2): If a Talmid in front of the judge sees Zechus for the Oni and Chov for the Ashir, if he is silent he transgresses Lo Saguru Mipnei Ish and mi'Devar Sheker Tirchak.

Aruch (Yeshev): The world is settled due to Tzedakah and Chesed of Ashirim. They have honor in front of Hash-m, so also we honor them. Alternatively, one remains wealthy only due to his Chesed and Emes, therefore one should honor him.

Rashi (Shabbos 153b DH Kevod and DH u'Chvod): One may cover up Divrei Torah to honor Shamayim, but not due to the honor of an Ashir. Rather, he should investigate the matter.

Tosfos (Shevu'os 31a DH v'Ro'eh): The Gemara often expounds a law from different verses in different places.

Maharil (Minhagim, Likutim 35, cited in Gilyon ha'Shas 86a): Rebbi did not want to be honored for his Torah. He preferred that the honor people show to him be for his wealth. The same applies to R. Akiva. A proof is that the Gemara does not say so about R. Yishmael bar R. Yosi, even though he also honored Ashirim. (We do not find that he was rich. R. Akiva was initially very poor, but later became very wealthy - Nedarim 50b.)

Tosfos ha'Rosh (Kesuvos 65a DH Tana): A woman rises with her husband's honor only when she is with him. (Then, he feeds her based on his wealth.) "One who feeds his wife through a third party gives more based on his wealth", i.e. of her father. She ascends with her husband, but does not descend with him. I say that for food, drink and clothing, she rises with her husband's honor even when she is not with him. One must honor his wife more than himself (Yevamos 62b). Regarding excessive delights, e.g. pillows and blankets, flutes and lamenters, she rises with him only when she is with him.

Me'iri (86a DH Ra'uy): It is proper for Chachamim and virtuous people to assign to everyone a place according to his honor, based on his Chachmah, wealth, or any attribute, as long as he has a good intent. This is why Rebbi and R. Akiva honored Ashirim. A verse teaches that when there are Ashirim who bestow Chesed and feed those in need, the world will be settled.

Chasam Sofer (Gitin 59a DH Bunis): Initially, Talmidim sat in the Beis Midrash according to their Chachmah. Among equal Talmidim, precedence was given to those with better lineage. Wealth meant nothing. R. Akiva and Rebbi initiated that for Talmidim of equal Chachmah and lineage, we give precedence to the wealthier one. Surely, we honor a multimillionaire more than a millionaire, for the former has a harder test to engage in Torah amidst such wealth and not rebel due to it. We need the verse to teach that one honors an Ashir more than an Oni, if they have the same Chachmah and lineage. Also the Oni is tested, through poverty and afflictions!

Sha'arei Teshuvah (of R. Yonah, 3:199): One may not flatter a Rasha due to his wealth, with intent to get benefit from him. One may honor Ashirim, but not Resha'im.

Pele Yo'etz (Chanufah): Some ignorant people think that honoring Ashirim is flattery, and it is good to disgrace them, to evade flattery. This is wrong. It is proper to honor them, like Rebbi and R. Akiva did. Hash-m bestowed wealth on them. This shows that He wants us to honor them. Especially one who benefited from them must honor them. Presumably, an Ashir does more Mitzvos than others. His Tzedakah redeems his Aveiros. Even if he acted improperly, one should not disgrace him so much. "If you were not Tudus (who financed Chachamim), I would excommunicate you)!" (Pesachim 53a)

Orchos Tzadikim (Sha'ar ha'Chanifus DH ha'Teshi'i): One may not speak highly about Resha'im and honor them even Derech Shalom, the way one honors Ashirim due to their success, and not due to their true importance.

Poskim

Shulchan Aruch (CM 9:7): If a Talmid sitting in front of his Rebbi sees Zechus for the Oni and Chov for the Ashir, he must defend him. If he is silent, he transgresses "mi'Devar Sheker Tirchak."

SMA (18): The same applies when both litigants are poor, or both are rich. Maharshal says that the Chidush is that even though there is a Mitzvah to honor his Rebbi and the Ashir, he may not be silent.

Bach (12): Maharshal supported himself from Sanhedrin 6b, which learns from Lo Saguru. This is wrong. Regarding two litigants, one of whom is harsh and the other is soft, the Gemara brought only the verse Lo Saguru. Tosfos (6b DH Lo) says that this connotes fear. Regarding one who sees Zechus for the Oni and is silent, the Gemara brings Lo Saguru and R. Chanin's Perush, that one should not cover up his words. Both litigants are Tzadikim, so there is no fear. The concern is only for honor of the Rebbi. It is a greater shame to the Rebbi when he did not look hard enough to find Zechus for an Oni, until his Talmid found it.

Maharsha (Chidushei Agados Shevu'os 31a DH v'Ro'eh): This is not only when he sees Zechus for the Oni. The Gemara discusses this case because it is common to refrain from telling the reason to obligate the Ashir, due to his honor. This is why in Sanhedrin we learn from Lo Saguru, i.e. due to fear of the Ashir.

Shach (8): The Maharshal says that regarding an Ashir, one might have thought that since also his honor will be impinged, perhaps one may be silent. The Maharsha and Bach did not explain like this.

Taz: The Maharal of Prague said that an Oni has greater rights. If one sees Zechus for the Ashir, he may be silent. He learns from "v'Dal Lo Sehedar b'Rivo." I.e. a judge may not favor an Oni, but one who is not a judge, just he sits in front of his Rebbi, may be silent and not cause a loss to the Oni through speaking.

Rebuttal (Birkei Yosef 23 DH v'Chazisei): We learn from mi'Devar Sheker Tirchak. If one does not say why the Ashir is exempt, he did not distance from Sheker! Perhaps this is why the Rambam brought both verses. Without mi'Devar Sheker Tirchak, one might have thought like Maharal, that one may refrain from causing the Oni to lose. Perhaps Reish Lakish (based on our text, this should say R. Yehoshua ben Korchah - PF) explains that the verse teaches that one should not fear [to correct] the Rebbi, and R. Chanin explains it to teach that one should not refrain due to honor of a litigant.

Taz: R. Yonah explains Oni and Ashir like Rashi (Devarim 1:17), that one should not say 'I will not blemish the Ashir's honor. Now I will say that he is exempt, and when they go outside, I will tell him to pay.'

Pischei Teshuvah (14): The Urim (10) v'Tumim (3) agrees with Maharshal. However, he says that the Gemara discusses Zechus for the Oni, lest the Talmid think that even though letter of the law the Oni is exempt, but based on intellect, we must say that the Ashir is correct, for surely one who has affluence would not [unjustly] claim from one who lacks! However, there is an opposing reasoning. An Oni is prone to deny the truth, lest he [need to pay and] go hungry. Therefore, one may not be silent. This is Sheker, for Torah law is Emes.

Kitzur Shulchan Aruch (29:3): One should consider every person to be greater than himself. If he is richer than you, you must honor him, like we find that Rebbi honored Ashirim. If Hash-m gave to him wealth, presumably he deserves it.

Aruch ha'Shulchan (OC 136:2): One who bought all the Aliyos to the Torah should distribute them properly according to honor, and not disgrace the Torah. We honor Ashirim regarding Aliyos, for they pay expenses of the Beis ha'Keneses.

Divrei Malkiel (5:64 DH Al): If it is not honorable for rich women to go to the same Mikveh as poor women, they should build a beautiful Mikveh special for rich pampered women, and a simple inexpensive Mikveh for poor women.