The Torah forbids a kohen from marrying the following women:
- a gerusha (a divorced woman)
- a halala (the child of a relationship forbidden to a kohen, e.g. the child of a kohen and a divorced woman)
- a zona (usually translated as a harlot, in this context it means someone who has had sexual relations with a man who is forbidden to her, e.g. an incestuous relationship)
In addition, the kohen gadol cannot marry an almana (a widow).
Our Gemara quotes a baraita that teaches that if the kohen gadol marries three widows he is only liable for having transgressed one prohibition. The Gemara objects that cases similar to this one appear to hold the transgressor liable for each act separately. In response the Gemara concludes that the baraita must be talking about a case where there were not three separate women, rather the kohen gadol married a woman who was a widow from three different marriages. The baraita is teaching that although this widow is a widow three times over, she is not perceived by the halakha as a threefold widow, but simply as a widow.
The baraita teaches that sometimes the order of the woman’s marriage will make a difference. If the kohen gadol marries a woman who was first an almana, then a gerusha, then a halala and finally a zona, he will be held liable for four separate forbidden relationships. If, however, the woman was first a zona, then a halala then a gerusha and finally an almana, he will only be seen as having one transgression. The Gemara explains this difference according to the opinion that en issur hal al issur – that once there is an existing prohibition a new prohibition cannot be added to the first one – except in the case of an issur mosif – when the new prohibition adds an element that did not exist previously. As an example, the almana is forbidden to the kohen gadol but not to an ordinary kohen. When she becomes a gerusha, a new prohibition is added – now she cannot marry an ordinary kohen either. Thus, the add-on of the new, additional status, is significant for the kohen gadol, as well.