A mishnah on today’s daf reads:
With regard to one who went overseas with his wife, and returned with his wife and children, and said: “This is the woman who went overseas with me and these are her children,” — he is not required to bring proof with regard to the lineage of the woman, nor with regard to the lineage of the children. If he said: “My wife died and these are her children,” — he must bring proof that the children were born to his wife, but he does not need to bring proof with regard to the lineage of the woman.
If he says: “I married a woman overseas, and this is she, and these are her children,” — he must bring proof with regard to the lineage of the woman, but he is not required to bring proof with regard to the lineage of the children. If he said: “I married a woman overseas and she died, and these are her children,” — he is required to bring proof with regard to both the lineage of the woman and the children.
Because this mishnah focuses on lineage, Rashi and all the major halakhic codes assume it is talking specifically about a priest who needs to demonstrate that his children can inherit the priesthood. According to the mishnah, if he and his wife went overseas for a time and returned together with their children, it’s assumed that her fitness to marry a priest was proven prior to their marriage and therefore her children are fit to inherit the priesthood. If, however, the man returns with children but no wife, or a new wife and children, or children by a new wife who has since died, then he needs to prove the new wife’s lineage and/or the children’s maternity.
Regarding maternity, the Gemara adds an additional element — it depends on the age of the children:
The sages taught that if a man says: “I married a woman overseas,” — he must bring proof with regard to the lineage of the woman, but he is not required to bring proof with regard to the lineage of the children. And he must bring proof with regard to the lineage of the adult children, but he is not required to bring proof with regard to the lineage of the minor children.
Small children are likely clinging to their mother (as those of us who have ever traveled internationally with little children can surely attest) and if her lineage has been vetted, theirs can be assumed. With adult children, particularly if their mother has died, their lineage must be proven.
We have seen throughout this chapter that the rabbis are concerned about ensuring that lineage — particularly of priests and their families — stays pure. There are a few reasons for this. Priests were (and still are, in many Jewish communities) called upon to perform a variety of ritual functions, from blessing the congregation with a special priestly benediction, to being called up to the Torah for the first aliyah, to accepting a ritual payment to redeem firstborn baby boys — so it’s important to know who these folks are. The rabbis are also planning for the future rebuilt Temple in Jerusalem; they want to ensure there are priests ready for service. For all these reasons, it’s important to know who the fit priests are.
In the late 20th and early 21st centuries, another way to interrogate priestly lineage has emerged. A number of scientific studies in the US and Israel have discovered a Y-chromosome priestly haplotype, seeming to demonstrate that there really may be an identifiable bloodline unique to Jewish priests. While the science is fascinating, it remains to be seen if such research will influence ritual outcomes. For now, we need to do what our ancestors did — take the father’s word for it, or do a little digging.
Read all of Kiddushin 79 on Sefaria.
This piece originally appeared in a My Jewish Learning Daf Yomi email newsletter sent on October 31st, 2023. If you are interested in receiving the newsletter, sign up here.
