Halakhah do Malachiasza 2:18

A man who has sexual relations with an idol worshiper, if zealots have not killed him and he has not received lashes at the hands of the court, his punishment is explicit in the words of tradition (Prophets), that he receives excision, as is written, “…For Judah has profaned the holiness of God which He loves, and has married the daughter of his strange god. May God cut off the man that does this, he that calls and he that answers…” (Malachi 2:11-12). He shall not have a caller among the wise nor a responder among the students. Note: This sin has a deficit which is not present among all the other sexual proscriptions, for the son derived from a (Canaanite) female slave or from a Kuthite (non-Jewish) female is not considered his son, as opposed to descendents from other sexually proscribed women (Tur in the name of Rambam). One who has sexual relations with an idol worshiper in public, whose law is that zealots kill him, as will be explained Choshen Mishpat chapter 425, is included in the classification of sexual proscriptions, and the law is that he should permit himself to be killed rather than transgress (Beit Yosef in the name of Orchot Chaim in the name of Rambam) as is the case with other sexual proscriptions and as explained in Yoreh Deah chapter 157.

A man who has sexual relations with an idol worshiper, if zealots have not killed him and he has not received lashes at the hands of the court, his punishment is explicit in the words of tradition (Prophets), that he receives excision, as is written, “…For Judah has profaned the holiness of God which He loves, and has married the daughter of his strange god. May God cut off the man that does this, he that calls and he that answers…” (Malachi 2:11-12). He shall not have a caller among the wise nor a responder among the students. Note: This sin has a deficit which is not present among all the other sexual proscriptions, for the son derived from a (Canaanite) female slave or from a Kuthite (non-Jewish) female is not considered his son, as opposed to descendents from other sexually proscribed women (Tur in the name of Rambam). One who has sexual relations with an idol worshiper in public, whose law is that zealots kill him, as will be explained Choshen Mishpat chapter 425, is included in the classification of sexual proscriptions, and the law is that he should permit himself to be killed rather than transgress (Beit Yosef in the name of Orchot Chaim in the name of Rambam) as is the case with other sexual proscriptions and as explained in Yoreh Deah chapter 157.

(Samekh) ‘Paved is the path of the straight’ that walk ‘in the way of charity,’ which is [what provides for] the maintenance of the world. ‘Happy is the one who reflects upon the destitute,’ and especially on the day of a joyful party and a holiday, as it is elucidated in the Zohar 2: 88b. And these are its words:
Come see that on all the other times and festivals, a man must rejoice and make the poor rejoice. And if he rejoices alone and does not give to the poor, his punishment is great, etc. About him it is written (Mal. 2:3), “And I will strew dung upon your faces, the dung of your festivals.” But if he rejoices on Shabbat – even though he does not give to the other – He does not give him a punishment like the other times and festivals, as it is written, “the dung of your festivals,” and not “the dung of your Shabbats.” And it is [also] written (Isaiah 1:14), “Your new moons and your holidays My soul does hate,” but Shabbat is not mentioned. And for this reason, it is written (Exod. 31:17), “Between Me and between the Children of Israel.” To here [are its words].
[However we need to understand] the reason that on festivals one needs to make the poor rejoice more then on Shabbat; and also what is the relevance of new moons here, such that it is written, “Your new moons and holidays My soul does hate,” whereas in the Zohar it is not mentioned that one needs to rejoice on new moons; and also that which it says, “And that is what is written, ‘Between Me and between the Children of Israel.’” It appears to me that the holy days are supernal guests, and one needs to make the guests rejoice. And this is their joy – to have the miserable poor rejoice. From this they take their portion. In order to grasp the point of the matter, I will tell you a parable about a king who visited a villager under his rulership. And [the villager] recognized him, but did not put his attention to honoring him properly. And [so] the king got angry with him. But when [the king] raised his eyes, a messenger came to him sent by another villager. [The message was], “If it would be good for the king, let him come to a party that I will make for him.” And [so] he came to the house of that man. But behold that man also did not pay attention to the king, and he also did not honor him. Then ‘the king broke out into a great anger.’ He said ‘with rage and fury,’ “[He] ‘shall be [torn by his] limbs and his home shall be a dunghill,’” as the act of this one was worse than the first man. [That is] because the king came to the first on his own, whereas this one sent for him. And the king also got angry at the messenger, as he was the [immediate] cause of his embarrassment. And behold, on Shabbat which is ‘fixed and standing’ and the [supernal] guests come on their own, He does not punish [those that do not share with the poor] much. But [this is not the case] on festivals and holidays which are [set] by Israel, like the statement of [the Sages], may their memory be blessed, “‘Which you shall proclaim them (otam)’ (Lev. 23:2) – [do not] read [‘them,’ but rather], ‘you (atem)’” (Rosh Hashanah 24a). And if one does not honor the guests then, his punishment is great. For this reason, it stated, “Your new moons and holidays My soul does hate” – since the [holidays] are [established by way] of the new moons, and He gets angry with the messenger as well. And for this reason, it said, “And that is what is written, ‘Between me and between the Children of Israel.’” [This is] since Shabbat is ‘fixed and standing,’ and we accordingly say (in the holiday prayers), “Who sanctifies the Shabbat, Israel and the [holidays]” – as Shabbat is a sign between Him and the Children of Israel, whereas the festivals are a sign between the Children of Israel and Him. And [it is also] because the Shabbat is ‘fixed and standing,’ whereas holidays are [established] by Israel. And understand [this]. And [it is] also because one needs to appear before the Lord on festivals and [holidays] – as it is stated (Deut. 16:16), “all your males shall appear” – [hence] at least at these times, he should be in the image and the likeness, the rich and the poor, together. And [he should then] not, God forbid, be like a beast.

It certainly stands to reason that a breach of law punishable by death at the hands of a zealot should not go completely unpunished in the absence of a zealot who feels called upon to act summarily. The Gemara, Sanhedrin 82a, states that the punishment for such a deed is karet, death at the hands of Heaven. In support of this statement the Gemara cites the verse, "Judah hath dealt treacherously, and an abomination is committed in Israel and in Jerusalem; for Judah hath profaned the holiness of the Lord which he loveth, and hath married the daughter of a strange god. May the Lord cut off to the man that doeth this" (Malachi 2:11-12). In rabbinic literature this punishment is referred to as karet me-divrei kabbalah, death at the hands of Heaven as recorded in the words of the Prophets.

He prohibited us from marrying heretics. And that is His, may He be exalted, saying, "And you shall not marry them" (Deuteronomy 7:3). And he explained what marriage is - "do not give your daughters to their sons or take their daughters for your sons." And in the explanation (Avodah Zarah 36b), they said, "The Torah forbade [it when it is] by way of marriage." And there are distinctions about the punishment of one who transgresses this negative commandment. And that is that when the one who has sexual relations with an Aramean has sexual relations in public - anyone who kills him while he is clinging to the sin has carried out the punishment, as Pinchas did to Zimri (Numbers 25:6-8). And they said (Sanhedrin 81a), "One who has sexual relations with an Aramean, zealots may attack him" - but with the conditions that we mentioned. And that is that he has relations with her in public, and [that the punishment is meted out] at the time of the act - like the story that happened (with Pinchas and Zimri). But if he did not do this in public or he [already] separated and the zealots did not attack him, he is liable for excision. However this excision is not made clear in the Torah: They said, "[When] zealots did not attack him, what is [the law]?" And it is explained that it is excision (cutting off), from His saying, "for Judah has profaned what is holy to the Lord - what He loves - and espoused daughters of alien gods. The Lord will cut off from the man that does this all living offspring" (Malachi 2:11-12). [This] implies that it is with excision. However when it becomes confirmed about a man - with witnesses and a warning - that he had sexual relations with an Aramean, he is lashed, by Torah law. And know this. (See Parashat Vaetchanan; Mishneh Torah, Forbidden Intercourse 12.)

And [it] is practiced in every place and at all times by males and females. Anyone who transgresses it and consecrates an [animal] with a blemish - and even at this time - violates this negative commandment. And from what appears, there would not be lashes with this, since there is no act [involved] with it; but I saw that Rambam, may his memory be blessed, wrote (Mishneh Torah, Laws of Things Forbidden on the Altar 1:2) [that] one who consecrates an [animal] with a blemish is lashed. And maybe he makes it like one who exchanges [a sacrifice] about which there is lashes even though there is no act [involved] with it - as [in that case, we see the impact of his words - since] this and that are consecrated. And to him shall we listen 'and we will seek Torah from his mouth, as he is an angel of the Lord of hosts.'

From the laws of the commandment is that which they, may their memory be blessed, said (Sanhedrin 81a) that zealots would attack one who has sexual intercourse with an Aramean (gentile) publicly in the eyes of ten or more Israelites. And the proof of the thing is the story of Pinchas and Zimri. But the zealot is nonetheless only permitted to attack him at the time of the promiscuous act, and like in the story that happened; as it is stated (Numbers 25:8), "and the woman through her belly." But if he separated [from her], we do not kill him, but [rather] bring him to the court and they administer lashes [upon] him, since he did the act publicly. [If] the zealots did not attack him and the court did not administer lashes [upon] him, we know from the words of tradition that he is [punished] by excision, as it is written (Malachi 2:11-12), "and he who husbands (read here as, who has sexual intercourse with) the daughter of a foreign god. The Lord will excise the man that does it." And a gentile who has sexual relations with an Israelite - if she is a married woman, he is killed over her; but, if not, he is not killed. But a Jew who wantonly has sexual relations with a gentile woman - even [if it is] by way of harlotry - she is nonetheless killed, since a mishap happened to an Israelite through her, like the law of an animal. And this thing is explicit in the Torah, as it is stated (Numbers 31:16-17), "They were the ones that were with the word of Bilaam against the Children of Israel, etc. and any woman that could know a man sexually they killed." [This] and the rest of its details are elucidated in Avodah Zarah and Yevamot and Kiddushin (see Mishneh Torah, Laws of Forbidden Intercourse 2).