Vayikra 19:2
Speak to the whole Israelite community and say to them: You shall be holy, for I, the LORD your God, am holy.
Rashi
SPEAK TO THE WHOLE ISRAELITE COMMUNITY: The addition of the words כל עדת teaches us that this section was proclaimed in full assembly because most of the fundamental teachings of the Torah are dependent on it (contained in it).
YOU SHALL BE HOLY: This means, keep aloof from the forbidden sexual relations just mentioned and from sinful thoughts. … whereever you find in the Torah a command to fence yourself in against such relations you also find mention of “holiness.”
Ramban
But according to my opinion, this separation is not to separate from sexual transgressions, like the words of the rabbi (Rashi). But [rather], the separation is the one mentioned in every place in the Talmud where its practitioners are called those that have separated themselves (perushim). And the matter is that the Torah prohibited sexual transgressions and forbidden foods, and permitted sexual relations between husband and wife and the eating of meat and drinking of wine. If so, a desirous person will find a place to be lecherous with his wife or his many wives, or to be among the guzzlers of wine and the gluttons of mean. He will speak as he pleases about all the vulgarities, the prohibition of which is not mentioned in the Torah. And behold, he would be a scoundrel with the permission of the Torah. (emphases added) Therefore, Scripture came, after it specified the prohibitions that it completely forbade, and commanded a more general rule — that we should be separated from indulgence of those things that are permissible.
Rabbi Adin Steinsaltz
Parashat Kedoshim is full of commandments, which include the prohibitions on stealing, lying, cheating, and so forth. At first glance, they do not appear to be special requirements or standards that an ordinary responsible person could not meet. On the whole, these are practices that are, more or less, commonly observed by the average person throughout the world, irrespective of religion or cultural background.
[Why does such basic moral behavior merit the word “holy”?]
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One would think that attaining holiness would require special safeguards and practices; but from here it seems that as long as one refrains from a few contemptible acts, that is all that is required to be holy. How can this be? … the definition of holiness that emerges from it is rather modest. It would seem to be devoid of any spiritual demand or attempt to elevate people to a higher sphere.
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But a person can change, as can his environment, and as a result, what was once easy to avoid can now be an extraordinary challenge.
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Sometimes, when a person hears, sees, and discovers all these things from below [that terrible sins do occur in the world], he finds that being holy is truly not a simple matter.
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Overall, many of the requirements in Parashat Kedoshim fall under this same overarching message: “Behave like a responsible person.” No more is required.
When we talk about the struggle of life from the perspective of an ordinary person, we speak of two types of enemies. On the one hand, there are overt embodiments of forces of evil. On the other hand, there is a subtler enemy that is no less potent and dangerous: erosion, where nothing out of the ordinary seems to happen.
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The positive and negative commandments that appear here, and which characterize holiness, are things that generally do not suddenly erupt but, rather, are situations that a person gets dragged into gradually, where each time it becomes increasingly easier to be drawn in.
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This process does not happen all at once, or because the burden of piety and morality is suddenly impossible to bear. It is just that bearing this burden on a daily basis is incredibly taxing.
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Bringing a korban every once in a while is simple. But to fulfill all the various major and minor requirements listed in Parashat Kedoshim every day is quite another story. Not for naught does the Torah say, “Everyone shall revere his mother and his father” (Lev 19:3). Anyone who has any experience in this knows how difficult it is. It is something that we are faced with every day, and it can be especially challenging when one’s father and mother are themselves not exceptionally holy people.
This struggle is the fundamental struggle for holiness. Parashat Kedoshim presents a long list of minor requirements, none of which is extraordinary on its own, but each one recurs day after day. This very requirement to maintain this routine without succumbing to jadedness and despair — that itself creates the highest levels of holiness.
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[to be holy] We agree to take upon ourselves the million termites of life, which appear every day and at every hour, from the time we rise in the morning until we go to sleep at night. The solution is to emulate God; when we bring God into the picture, we begin to understand the meaning of the verse, “I am God — I have not changed” (Mal. 3:6). God does not change; He remains holy no matter what the circumstances.
Rabbi Yehudah Leib
No one can attain holiness except by negating his own self…Rashi teaches: “Wherever guard is kept regarding interpersonal borders [avoiding sexual misdeed], there you will find holiness.”
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“You shall be holy.” Rashi comments: “Be careful about sexual misdeed and transgression.” Ramban reads it: “Sanctify yourself within the domain of the permitted.”
In my humble opinion Rashi has the correct intent here. Surely, “You shall be holy” is one of those commandments that has no fixed limit. The more you abstain, the greater the holiness you attain, and there is no end to this.
The Kedushah Crisis: Sexual abstinence of married men roils Hasidic sects of Gur, Slonim, and Toledot Aharon, Benjamin Brown, Tablet Magazine, February 24, 2019
Kedushah (holiness) was developed as a pietistic ideal for the virtuous few, encouraging [sexually restrictive behavioral norms among] married men … today, the Hasidic groups of Gur, Slonim and Toledot Aharon have radicalized this ideal by imposing it on the community as a whole. Gur’s version is the most restrictive and the only formalized as a set of ordinances …
a very public dispute about the kedushah ordinances erupted in the Israeli arena in 2009, when a Gerer woman, Sarah Einfeld, appeared in a short documentary film titled in English Shrew … In her blog, she reported on the “repression” of women in Gur … highlighting the suppression of sexuality and intimacy under the regime of kedushah ordinances.
…Prominent Litvish rabbis have pointed out that kedushah norms are at odds with the Halacha while also being offensive to women and harmful to men’s mental and moral well-being. Rabbi Y. I. Sher, the past head of the Slobodka Yeshiva, even accused the Hasidim of hypocrisy. [The rules that Brown is referring to were instituted in Gur after the Holocaust.]
Vayikra 19:17-18
You shall not hate your brother in your heart. Reprove your neighbor but incur no guilt because of him. You shall not take vengeance or bear a grudge against your neighbor. Love your fellow as yourself: I am the LORD.
Rabbi Yehudah Leib
Do not cast the entire burden of sin onto the transgressor. Involve your own self in this matter and repent for the sin.
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“Love your neighbor as yourself” we interpret as a [causative] form referring to the love of God. Where have we found [it written] that a person is supposed to love himself! Then what does “as yourself” mean? The meaning rather is: “Make God as beloved to your neighbor as He is to you.
[Rabbi Arthur Green interprets the last part as bearing witness to the knowledge that we are all made in the image of God. Love your neighbor as yourself, means recognizing that we are all the image of God, modeling that as you love your neighbor as the image of God, so that your neighbor will also love you as the image of God.]