"For three days before their idolatrous festivals it is not permitted to buy or sell them anything. It is also forbidden to give or take any help from them, to change any money with them, to pay them back any debts or allow them to pay back debts."

In the Abhodah Zarah, 78c (the Perusch of Maimonides, fol. 8) it says:

"All the festivals of the followers of Jesus are forbidden, and we must conduct ourselves towards them as we would towards idolators. The first day of the week is their principal feast, and it is therefore forbidden to do any business whatsoever with those who believe in Jesus on their Sabbath. We must observe the same rules on their Sabbath as we do on the feastdays of idolators, as the Talmud teaches."

2. A JEW MUST NOT USE ANYTHING WHICH PERTAINS TO THE WORSHIP OF CHRISTIANS

In Iore Dea (139,1) it says:

"It is forbidden to have anything to do with idols and everything that is used in their form of worship, whether they are made by the Akum or by Jews."

3. IT IS FORBIDDEN TO SELL TO CHRISTIANS ANYTHING CONNECTED WITH THEIR IDOLATROUS WORSHIP

The Abhodah Zarah (14b, Toseph) says:

"It is always forbidden to sell incense to an idolatrous priest, for it is evident that when he asks for it he wants it for no other purpose but to offer it before his idol. Anyone, therefore, who would sell it to him sins against the precept which forbids us to place a stumbling-block before the blind. It is also forbidden to sell candles to gentiles for their Feast of Candles. Candles however may be sold to them on other days. Neither is it permitted to sell a chalice to a gentile which a Jew has bought after a Goi has broken it and thrown it away. It may only be sold again to a gentile after it has been completely made over. For after it has been broken just once it can be used still to hold the wine which is offered in honor of their idol." Then follows the prohibition as to the selling of books to Christian priests, as we have seen above. Even the work of binding such books is forbidden to a Jew. In Iore Dea (139,15) it says:

"It is forbidden to bind the books of the Akum, with the exception of law books. It may be done, however, if refusal to do so should cause enmity, but only after every effort has been made to refuse such work."

Likewise in Iore Dea (151,1, Hagah):

"It is not permitted to sell water to an Akum if it is known that it will be made into Baptismal water."

Mention is also made of many other things which it is forbidden to sell to Christians, such as: cloth from which priestly vestments and banners may be made; paper and ink which may be used for writing books pertaining to their divine worship. It is forbidden to sell, or even to rent, houses to Christians which will be used by them as a place of worship. Nowadays, however, Jews trade with Christians, especially on Christian feast days, and also sell them houses knowing full well that certain Sacraments will be administered therein, such as Baptism, Holy Communion and Extreme Unction. The Talmud can give no reason for this, and in the Abhodah Zarah (2a, Toseph) it says:

"It is difficult to say by what right Jews nowadays trade with the Goim on their (evil) feast days. For although many of them commit all kinds of licentious acts and perversions on their feast days in honor of saints which they do not look upon as gods, yet every week they celebrate the Day of the Nazarene [Sunday] which has always been forbidden to us."

Bartenora, however, in his commentary on Abhodah Zarah (I, 2, fol. 7b) it says:

"Since, while we are in captivity, we cannot live without trading with them, and we depend upon them for our food and we must fear them, it is only forbidden to trade with them on their feast days.(8) Furthermore, it is permitted nowadays to trade with them on the actual day of their feasts, because the Rabbis are convinced that they do not worship their idols just because they trade with us. And what is forbidden in this book must be taken as applying directly to idolatry."

(8) Although Rabbi Ischmael says it is forbidden to trade with them for three days before their feast days.

Rabbi Tam,(9) however, contends that the Mischnah only forbids the selling of things to idolaters which will be used by them in the worship of idols, since they rejoice and worship their idols because they obtain the things necessary for that worship. He explains it thus (in Abhodah Zarah, 2a, Toseph):

"No one should wonder at this custom of ours. For, although we look upon them as idolaters, they can only offer up what they buy for money. Hence, our gain and their joy is not the reason for this prohibition, for they have enough money for these things, even if we did not trade with them."

(9) One of the authors of the Tosephoth, died in 1170.

4. THIS PROHIBITION DOES NOT APPLY TO ATHEISTS

In Iore Dea (148,5) it says:

"It is only permitted to send a gift to an Akum on one of their feast days if it is known that he does not believe in idols and does not worship them."

Maimonides has the same in Hilkhoth Akum (IX, 2):

"It is also wrong to send a gift to a Goi on their feast days unless it is certain that he does not believe in the worship of Christian idols, and does not serve them."