Question: I've been invited to a friend's house to be a guest at a Passover Seder. Is it okay to go? Is it okay to eat kosher food? To attend a Jewish wedding or Bar-Mitzvah?
Answer: If you read this column last month, you may remember that the Passover Supper (or Seder) was a sacrificial ritual prescribed by God for the Jewish people of the Old Testament. In Exodus xii we see that a Lamb was sacrificed and eaten with unleavened bread. While the observance of Passover was mandatory for pre-Christian Jews, it was clearly a forerunner of the sacrifice of the true Lamb of God on the Cross and in the Mass. A Christian would no more observe the Passover Seder than he would sacrifice goats or pigeons, as the Old Testament Jews also did.
The First Commandment clearly tells us that we must not worship any false "gods." Obviously, that tells us that we may not worship the Buddha, or pour out libations to the snake "god," or wear the mark of the Hindu "gods" on our forehead, or seek the blessing of an Indian witch doctor. To the degree that they are real at all, the false "gods" can be nothing other than the works of the devil. (See the inset, below.)
Judaism, however, is a special case. Jewish people, of course, worship the same true God as Christians. The Church considers the Old Testament Jews and their Scriptures to be a part of Its own heritage. Yet, many features of Old Testament worship have been superseded by the sacramental system of the New Testament. Taking part in the sacrifices of the Old Testament may not be the worship of false "gods," but, since the time of Christ, such sacrifices are the false worship of the true God.
Eating kosher food is a different matter. The Law of Moses forbade the Jewish people to eat certain kinds and combinations of food; certain procedures for the slaughter and preservation of meats were mandated. These regulations are no longer in effect (Cf. Acts x). However, such foods have not been offered up in false sacrifice to God. A kosher hot dog, for example, may be no more than so many days old, may contain no pork, and may have been prepared under rabbinical supervision; but it is not an object or an instrument of false worship. Christians, therefore, may have all of the lox or pastrami they care to eat. On the other hand, it would, of course, be wrong to insist upon observing the kosher food laws as a binding religious requirement.
Normally, a non-Jew attending a Jewish wedding or Bar-Mitzvah, does so in the role of a friend fulfilling a social obligation. A Bar-Mitzvah is the ceremony by which the members of a Jewish community recognize the fact that a young man has become an adult. Even though it is a religious ceremony, one can attend it and remain completely a spectator (something quite impossible at the sacrificial banquet that is the Seder). Attending a Bar-Mitzvah would be much like attending a graduation -- the spectators need take no part in the ceremony.
Much the same can be said for attending the wedding of non-Catholics, with but one proviso. Non-Catholics are free to marry before a minister, a rabbi, or a civil official. However, they are bound by the same demands of indissolubility as Catholics. That is to say that, from God's perspective, non-Catholics may not divorce and re-marry any more than Catholics may do so. Consequently, it would be wrong for a Catholic to attend the wedding of a couple that was not free to marry because of a previous marriage(s).
Catholics are free to fulfill their social obligations to attend non-Catholic ceremonies such as funerals, (valid) weddings, and Bar-Mitzvahs as non-participants. We may not take an active part, serving, for example, as a God-parent or witness in a non-Catholic baptism or wedding. Nor may we take part in non-Catholic worship, be it in a church or synagogue, or in a ceremony like a seder, conducted at home. Without violating the First Commandment, we most certainly may not participate in the worship of false "gods" or in the false worship of the true God.