Which Relatives are Disqualified From Testifying Together or About One Another?

The Shulhan Aruch (Hoshen Mishpat 33) rules that "Kerobim" – relatives – are disqualified from serving as witnesses together, or for or against each other. To which kinds of familial relationship does this Halacha apply? If two people are distantly related to each other, are they disqualified from testifying together or about one another?

The Halachic terms used in reference to the level of relationship that disqualifies witnesses are "Rishon Be’rishon" (literally, "first with first") and "Sheni Be’sheni" ("second with second"). The term "Rishon Be’rishon" refers to family members of the same generation, meaning, brothers. It is clear that two brothers cannot serve as co-witnesses, and that a man cannot testify about his brother. The term "Sheni Be’sheni" refers to first cousins, the children of brothers. They, too, are disqualified from testifying together or about one another.

Halacha classifies the relationship between father and son under the category of "Rishon Be’rishon." Even though they belong to different generations, the unique closeness of their relationship renders it a "Rishon Be’rishon." As such, the relationship between a man and his grandson would be considered a "Rishon Be’sheni," and they would be disqualified from testifying together or about one another. Even though they are two generations apart, they are nevertheless considered "Kerobim" because the father-son relationship is considered "Rishon Be’rishon." With regard to a man and his great-grandson, different views exist among the Poskim as to their status vis-à-vis testimony. It is clear, however, that siblings, a father and son, first cousins, and a grandfather and grandson are disqualified from testifying together or about one another.

Summary: Two "Kerobim" (relatives) are disqualified from serving as witnesses together, or from testifying about one another. This includes brothers, first cousins, a father and son, and a father and grandson. There is a debate among the Halachic authorities as to whether this disqualification also applies to a great-grandfather and great-grandson.