1,940. Two Brothers, Married to Two Sisters, and Both Brothers Die

Yibum v’Chalitzah 7:1

Let’s say that two brothers were married to two sisters. They both died and we have no way of knowing which one of them died first. In such a case, a surviving third brother may not perform yibum with them. Since they both have levirate bonds to him, they must perform chalitzah to the exclusion of yibum. This is true even if one of the women is prohibited to the yavam as a secondary relation, or by a positive or negative commandment. However, if one of them is a prohibited relation, such as his wife’s mother or daughter, then the sister is permitted and he may perform either yibum or chalitzah with her. This is because both sisters didn’t have a levirate bond since prohibited relations have no such obligation.

Yibum v’Chalitzah 7:2

Let’s say that there were four brothers, two of whom died. One yevama was forbidden to one of the surviving brothers as a prohibited relation, and the other yevama was forbidden to the other surviving brother as a prohibited relation. The yevama who is prohibited to yavam A is permitted to yavam B, and the one who is prohibited to yavam B is permitted to yavam A. In each case, only the permitted yevama has a levirate bond to each brother, who may perform either yibum or chalitzah with the permitted woman.