1,938. Maamar Followed by a Get
Yibum v’Chalitzah 6:28
One might ask why the surviving brother doesn’t just perform chalitzah with the woman who was given maamar, and who has levirate ties from two men, and then perform yibum with the widow of the other brother. This is a decree that was enacted to prevent people from thinking that when there are two yevamos from the same house, one should perform chalitzah with one and yibum with the other. This is why they prohibited performing yibum with the widow.
Yibum v’Chalitzah 6:29
Let’s say that the second brother gave maamar to the yevama and then he gave her a get to cancel it, after which he died. This woman is permitted to the third brother because the maamar that prohibited her was voided. The third brother may then perform either chalitzah or yibum with her.