Leviticus 19:2

2. Kedoshim tehyu. Be separated from the inappropriate sexual relationships and from sin. Because every time you find a precaution around erva you find holiness. "Stay away from a prostitute and other disqualified women...I am God your sanctifier "(Leviticus 21:7); "And he will not profane his seed, I am God his sanctifier" (Leviticus 21:15); "Be holy, do not take a prostitute woman or disqualified woman, etc. (Leviticus 21:6,7).

Speak with the whole congregation of the sons of Israel, and say to them: Ye, shall be holy, for I the Lord your God am Holy.

The entire community of the Children of Israel means that the resident alien is not included. Like the Israelites, resident aliens were told not to commit any sexual offenses; therefore they must now be specifically excluded from most of the subsequent commandments.

However, Scripture mentions the current passage immediately after the passage dealing with sexual offenses, so that one should not think that resident aliens may remain in the land, if they refrain only from sexual crimes. In fact, there are other commandments which they must follow in order not to be expelled from the land: i.e., the Ten Commandments which are herein mentioned. Be holy This is the prohibition against idolatry. It is given on account of the fact that I , God your God, am holy (which corresponds to the utterance that most people count as the First Commandment). “Do not swear by My name…” [:12] corresponds to the Commandment “You shall not swear…” [Exodus 20:7]. You will observe My Sabbaths corresponds to “Remember the Sabbath day…” [Exodus 20:8]; Each of you will revere his mother and father corresponds to “Honor your father and your mother…” [Exodus 20:12]; and “Do not stand idle when your fellowman is in danger” [:16] corresponds to the Commandment “You shall not murder” [Exodus 20:13]. The passage of the betrothed bondmaid [:20] warns us not to commit adultery with a free-woman. “Do not steal; do not deny; do not lie” [:11] and “Do not exploit your neighbor” [:13] correspond to the three remaining Commandments.

SPEAK UNTO ALL THE CONGREGATION OF THE CHILDREN OF ISRAEL. Our Rabbis have already said. Quoted also in Rashi. that this section was addressed to the full assembly [of all Israel] because most of the fundamental principles of the Torah are dependent on it, this being the reason for the expression, speak unto all the congregation of the children of Israel. This section, however, was mentioned here in [the book of] Torath Kohanim because it contains laws concerning the thanks-offering, and also because it states the punishments He commanded us to execute on those who do the abominable deeds mentioned [in the preceding sections], as well as [those for] the forbidden sexual relationships. These subjects have been included in this book [of Torath Kohanim] for the reason that we have written at the beginning of this book.

קדושים תהיו, seeing that most commandments are designed to sanctify you and to be observed by you.

דבר אל כל עדת...קדושים תהיו; after the presence of G’d had manifested itself among the Jewish people, sanctifying them for eternal life, as had been the meaning of the verse in Exodus 19,6 “you shall become for Me a nation of priests a holy nation,” and taking into consideration G’d’s statement in Leviticus 11,45 “I have led you out of the land of Egypt in order to be your G’d and your becoming holy,” G’d had in the meantime separated the Jewish people from impurity through the legislation concerning forbidden foods, skin eczemas, ritual impurity contracted through cohabitation with menstruant women, or women afflicted with excretions from their vaginas at times other than when they were experiencing menstruation.
G’d had also elaborated on other ritual contaminations contracted through sinful contact. The objective of all these parts of Torah legislation was to establish a nation that could be described as “holy,” not least of it the legislation concerning incest.
At this point, i.e. after achieving this “holiness,” i.e. emulating the Creator’s holiness in the maximum manner possible for creatures, the Torah spells out this objective by saying כי קדוש אני, “For I the Lord am holy;” the message is that the original intention in creating man in the image of G’d (Genesis 1,26) had already had as its declared goal for this “image” to become something constant. The Torah now proceeds to list laws which appeared on the first of the Two Tablets, whose objective it is to ensure enduring life for the Jewish people as we explained on Exodus 20,11.

קדושים תהיו, “you shall strive to attain holiness.” The meaning of this verse is made clear in verse four where the Torah adds that “you must not turn to idols, etc;” even if the purpose of your preoccupation with idols is to understand why they are completely useless, so that you think that what you do is לשם שמים, “for the sake of heaven,” do not do so! Seeing that only the Lord is holy, there would be no point in studying other nations’ ideologies.