Tosefta su Salmi 106:78

One may not go to a [idolatrous] market-place that is in a village or in any of the surrounding cities because it looks like he is going to the market-places in those cities. These are the words of R. Meir. The sages say, "Only that village is forbidden. A market-place that is inside of a village is forbidden. If it is outside of the village, it is permitted. As for the nobility [?] of a village, it is forbidden to deal with them outside the village, but it is permitted inside the village. The shops that are crowned at each place are forbidden. If a man is in a caravan going from place to place and enters a village in which there is a market-place, let him not worry because it looks like he goes into an market-place. A market-place that was given by the kingdom, the state, or by the elite of the state are permitted. Only the market-place of idolaters is forbidden. One may go to an idolatrous marketplace and receive medical treatment so long as the treatment is for money(?) and not for life(?). One may not take from them houses, fields, vineyards, animals, slaves, or maidservants because it is as though one is rescuing from his hand. And he writes and deposits [a deed] in an archive. A priest contracts impurity to give testimony outside Eretz Yisrael. Just as he contracts impurity from outside Eretz Yisrael, so too he contracts uncleanness in a graveyard. And he contracts uncleanness [in order] to study Torah or to marry a woman. Rabbi Yehuda says, If he has someone with whom to study, he should not contract uncleanness, but if not, he should. Rabbi Yosei says, even if he has someone with whom to study, he should contract uncleanness for it is not from any man that a person should merit to learn, but with the person who can give that merit to him. They said about Yosef haKohein that he should contract impurity and go out [to study with[ Rabbi Yosei in Tzidon. A priest should not go ab road even to marry a woman unless they assured him. Merchants who moved up the time of a yarid or pushed it back, it is permitted. It is only forbidden at the time of the yarid alone. Four [instances of the word] “dust” are [used] figuratively [meaning “something akin to” or “a shade of”]: “the dust of usury,” “the dust of the seventh year,” “the dust of idolatry,” and “the dust of lashon hara.” The dust of usury: a man should not do business in a loan of his fellow. The dust of the seventh year: A man should not do business with an idolator in (idolatrous) fruit because of the shade of [that is, it is akin to, produce of] the seventh year. The dust of idolatry: One should not do business with an idol worshipper on the day of his festival because of the dust [or because it is akin to] of idolatry. The dust of lashon hara: One should not do business in as a favor to his fellow because of the shade of [it is akin to] lashon hara. Jews who are going to a yarid are permitted to do business with them, and on their return it is prohibited because they engaged in idolatry, but as for an idolator, it is permitted whether he is going or coming back. Idolators who are going to their debauchery, it is prohibited to do business with them but on their return it is permitted, because it is like idolatry and they have abandoned its worship. A Jew, whether going or coming, is prohibited. A Jew should not travel in a caravan to a debauchery even to go out and even to to before it and even to be there when it gets dark and even though one is fearful because of idolators or brigands or evil spirits, as it says, “you shall not go after other gods” (Deut 6:14). Rabbi Eliezer the son of Rabbi Yosei haGalili says, if you see a righteous person who is going out on a journey and you are planning on making the same journey, you should move your trip three days earlier or later to travel with him, as he is accompanied by ministering angels, as it says, “For he will command his angels to keep you in all your ways” (Ps 91:11). And if you see an evil person going out on a journey and you want to make the same journey, you should move your trip even three days earlier or later so as not to accompany him, because adversary angels accompany him, as it says, “Appoint a wicked man against him, let an accuser stand at his right hand” (Ps 106:6). Rabbi Shimon ben Elazar says, if young people say to you “build the temple!” do not listen to them. And if old people tell you, “destroy the temple!” listen to them, for the building of youths is destruction and the destruction of the old is building. Proof of the matter is Rehoboam the son of Shlomo. They asked Rabbi Yehoshua, what [is the law] of a man teaching his son a book in Greek? He said to them, Let him teach [it] at an hour which is not day or night, as it says, “And you will meditate in it day and night” (Josh 1:8).

One who slaughters livestock in order to to throw the blood for [purpose of] idol worship, or to use its fat as a burnt offering for idol worship, behold, this is [considered to be like] the meat of the sacrifices of the dead (Ps. 106:28). If once it was slaughtered he threw its blood for idol worship, or used its fat as a burnt offering for idol worship, this is what happened in Caesarea, and they came and asked the Sages, and they did not say whether [the meat from the sacrifice] was forbidden or permitted. One who slaughters in the [Temple] courtyard impure livestock, undomesticated animals, or fowl -- they are forbidden to derive benefit from, and needless to say for consumption. Ritually pure livestock, undomesticated animals, and fowl [slaughtered in the Temple courtyard] are permitted to derive benefit from. One who slaughters a tereifa, Rabbi Meir forbids deriving benefit and Rabbi Shimon permits deriving benefit. One who slaughters for [purposes of] healing, to feed idol worshippers, or to feed dogs, it is forbidden to derive benefit. One who slaughters but renders [the animal] carrion by his own actions, and one who [kills the animal by] stabbing, or by tearing loose [the windpipe], [if such] a slaughter is for idol worshippers it is permitted to derive benefit (see Hul. 2:6). One who slaughters ritually pure livestock, undomesticated animals, or fowl in the women's courtyard [of the Temple] , it is permitted to eat, and needless to say, to derive benefit.

One who slaughters in the name of the sun, the name of the moon, the name of the stars, the name of the [zodiacal] constellations, for the sake of Michael, minister of the great army, or for the sake of a small worm, behold, [in all those cases] this is [considered like] the meat of offerings to the dead, [from which benefit is forbidden (see Hullin 40a:2)]. One may not slaughter [so that the blood runs] either into the seas, or into the rivers (Hullin 2:9), or into murky water, but he may slaughter [so that the blood flows] into a goblet of water, or on a ship [he may let it flow] into a vessel, and if there is no place on the ship he can slaughter into the sea, and if he does not want to sully his house, he may slaughter inside a a vessel or inside a hole (ibid.). But in the market he should not do so because this is what is done by those who worship the stars. If he does this, he should be checked [to ensure he does not harbor heretical beliefs]. Meat that is found in the hand of a star-worshipper is permitted to benefit from; in the hand of a [Jewish] heretic it is forbidden to benefit from; from the house of a heretic, behold, it is [considered to be like] the meat of the sacrifices of the dead (Ps. 106:28), as it is said, "The slaughter of the heretic [is tantamount to slaughter] for the sake of star-worship (i.e., idolatry), and a their bread is the bread of star-worshippers, and their wine is the wine of libation [of star-worshippers], and their produce is [all considered] untithed (see Kutim 1:7), and their books are the books of sorcery, and their children are [considered to be] mamzers, and we do not sell to them, and we do not buy from them, and we do not marry their daughters (lit, "marry from them"), and we do not give [our daughters] to them, [and] we do not teach their children an occupation, and we do not [accept] treatment from them, either monetary treatment or medical treatment" (cf. Avodah Zarah 2:2). It so happened with Rabbi Eliezer ben Dama, the son of Rabbi Yishmael's sister, that a snake bit him, and along came Ya'akov, a man from K'far Sachnai, to heal him (Vienna Man. adds, "in the name of Yeshua ben Panteira," see also Y. Avodah Zarah II.2.11), and Rabbi Yishmael did not allow it. He said to him, "You are not allowed, ben Dama." He said to him, "I will bring you proof that he can heal me," but he did not have enough time to bring him proof before he died. Rabbi Yishmael said, "Ben Dama is fortunate that he departed to eternal peace, and did not tear down the fences of the Sages, before [divine] retribution came upon him," as it is said (Ecc. 10:8), "He who tears down a fence will be bitten by a snake." [And] it so happened with Rabbi Eliezer that he was apprehended on the words of the heretics (meaning ambiguous), and they brought him before the court to render judgment (Avodah Zarah 16b:15). The hegemon said to him, "Is an old man like you [really] occupied in such matters?" [Rabbi Eliezer] said to him, "The Judge is trusted by me." The hegemon thought that Rabbi Eliezer was talking about no one else but him, although Rabbi Eliezer did not intend [to refer to anyone] but his Father in heaven. The hegemon said to him, "Since you trusted only in me, thus I say: It is possible that such old ones [as yourself] error on such matters (i.e., listening to the words of heretics). [Thus, you are] acquitted; you are exempt." And at the time that he was freed from the court, he was sorry that he had been arrested on the words of the heretics, and his students came to him to console him, and he did not accept [their consolation]. [Thereafter,] Rabbi Akiva entered [Rabbi Eliezer's house] and said to him, "Rabbi, may I speak before you to ease your distress?" He said to him, "Speak." He said to him, "Perhaps one of the heretics said to you a word of heresy (i.e., one of his teachings) that pleased you." He said to him, "Yes." He said to him, "By the heavens, you reminded me! One time I was walking in the camp of Sepphoris, when I met a man of K'far Sachnai, and he said a word of heresy (Vienna Man. adds, "in the name of Yeshua ben Panteira," see also Avodah Zarah 17a:1), and I enjoyed it, and thus I was apprehended on the words of heresy, such that I transgressed the words of Torah, "Remove your way from her, and do not approach the entrance of her house" (Prov. 5:8), "for she has cast down many wounded" (Prov. 7:26). And thus Rabbi Eliezer says, "A man should always flee from ugliness, and from anything that resembles ugliness" (Avot D'Rabbi Natan 2:2).