Avos: 4:4 (notes)

Rabbi Levitas, a man of Yavneh, says: Be very, very humble in spirit, for the hope of man is worms: How can a man be proud at all - as in the end, the worms will be better than he? And about this he said, "Be very, very humble in spirit" - to emphasize the thing and say how great the punishment is for haughtiness and that is the proud one. And Rambam, may his memory be blessed, explained that he came to inform us that even though the middle point in all of the traits is the praiseworthy - like the trait of generosity, since both the spendthrift and the miser are bad and the middle is the [right] choice; and so with the trait of cruelty, that a person should not be cruel and [also] not completely merciful, as he should not have mercy on the wicked, and not be cruel to other people, rather the middle is the good path, to be merciful but to be cruel when needed; and so [too] totally with all (the intellect) [the traits], a man should grab the middle path and the moderate trait - yet this trait of haughtiness must be removed from oneself to the far extreme. As there is no trait more problematic than it; and most of the sins of the Torah depend upon it. And moreover, it causes forgetfulness of the Creator, may He be blessed, from the heart of a man - as it is stated (Deuteronomy 8:14), "And your heart grow haughty and you forget the Lord, your God." And this is what we learned [here], "Be very, very humble in spirit." And the sages of the Talmud have already argued about this thing in Tractate Sotah 5a - "One said, 'In excommunication is the one that has it and in excommunication is the one that does not have it at all.'" [This] is to say that a person should not be humble in spirit to the final extreme and not to be so lowly that people disparage him. Rather, he should be moderate in taking haughtiness - not to (beautify himself) [make himself proud], but not to lower his spirit to the utmost lowliness, that he not come to disgrace. And about this they said, "In excommunication is the one that has" much haughtiness "and in excommunication is the one that does not have it at all" - as he is not a person, but 'he is similar to the beasts.' "And the other one said, 'In excommunication is the one that has it at all'" - as it is so bad a trait that he must distance himself from it completely. And there should not be in him from it at all, like the opinion of Rabbi Levitas, and for the reason that we have written. And so is the law.

Rabbi Yoḥanan says in the name of Rabbi Shimon ben Yoḥai: Any person who has arrogance within him is considered as if he were an idol worshipper, as it is written here: “Everyone that is proud in heart is an abomination to the Lord” (Proverbs 16:5), and it is written there concerning the destruction of idols: “And you shall not bring an abomination into your house” (Deuteronomy 7:26). And Rabbi Yoḥanan said his own statement: Any person who has arrogance within him is considered as if he has denied the core belief in God’s existence, as it is stated: “Then your heart be lifted up, and you forget the Lord your God” (Deuteronomy 8:14).

"secretly": And you [may] ask, behold, Rabbi Bartenura explained in Mishnah Yoma 8:8 that desecration of the Name (chillul Hashem) is [committed by] one who sins and causes others to sin; and this is one who sins and others learn from him; and if so, you don't find it "secretly," etc. And it appears to me that it is found with a sin that it is impossible [to do] without being joined by another - for example the sexual prohibitions. And it is also certainly true that one who eats forbidden foods and the like by himself and no one sees him is not [causing] a desecration of the Name at all. And see Tosafot Yom Tov.

"There is no differentiation between unintentional, etc.": It is known that the one who is unintentional also needs atonement. But he is not like the one who is intentional - God forbid for the straight paths of God, may He be blessed, to equate the intentional with the unintentional in anything. Rather, the intention [of the mishnah] is that his punishment is in public - if it was intentional, the punishment is [for an] intentional [sin]; if it was unintentional, the punishment is [for an] unintentional [sin], etc. And see Tosafot Yom Tov.

Rabbi Yochanan ben Beroka says: Anyone who desecrates the Name of Heaven secretly, they punish him publicly: [Of course,] the desecration of the Name that is mentioned in the Talmud is public (by definition). And according to the importance of a man can there be a desecration for a small thing, as was said (by Rav Nachman in Tractate Chullin) (Yoma 86a), "How is desecration of the Name? (Rav said,) 'For example, [if] I took meat from the butcher and did not give him money immediately.'" Hence the sages and men of repute (need) to watch their deeds more than other people. And every man is according to his standing. 'And anyone who wants to take the name (and consider himself important in this regard), let him come and take [it].' And they said in Tractate Sanhedrin 74a that even for tying a shoelace (in the way of the gentiles), he should let himself be killed and not transgress. This is not by way of obligation, yet one should let himself be killed for this - as he is doing a commandment that sanctifies God, may He be blessed, and [so] 'he acquires his [share in the] world [to come] in an instant. But in three things everyone is obligated to let himself be killed for them; and if he transgresses and does not allow himself to be killed, it is a major sin [in itself] like idolatry, murder and sexual immorality. And the punishment for public desecration of the Name is greater than those three, as it is stated (Ezekiel 20:39), "As for you, House of Israel, thus said the Lord God, 'Go, every one of you, and worship his idols and continue, if you will not obey Me; but do not desecrate My holy name any more with your idols and your gifts.'" Behold, it is elucidated for you that He was more (in remembrance of) [exacting about] that which they were worshiping idols because they were desecrating His holy Name publicly than [because] of the idolatry itself. And [hence] that which we learned, "Anyone who desecrates the Name of Heaven secretly," is speaking about things that are a desecration of the Name in of themselves, like idolatry - as he is affirming [the idol's] divinity. And so too, the one who swears falsely with the Name of the Holy One, blessed be He - which is deceiving the minds of the creatures - is a desecration - as it is stated (Leviticus 19:12), "You shall not swear falsely by My Name, desecrating the Name of your God; I am the Lord."