what is yibum and chalitzha and why cant the kohen goddel perform them?
alan goodman, new york ny
Here is what we wrote in Background to the Daf:
2a) [line 12] CHOLETZ (CHALITZAH)
(a) If a married man dies childless, his widow must undergo Yibum (see below, entry 2b), as it states in Devarim 25:5-10. Chazal learn from the verses that there is a preference for the oldest brother to perform Yibum.
(b) If the brother chooses not to marry her, he must perform Chalitzah (a procedure in Beis Din that absolves her of the Mitzvah of Yibum - ibid.). He appears before a Beis Din of three (but see Insights to Yevamos 101:2) and states, "I do not want to marry her," after which his sister-in-law approaches him before the elders, takes off his right sandal and spits in front of him. She then declares, "This is what shall be done to the man who will not build up a family for his brother," and she is then free to marry whomever she wants.
(c) Since Yibum involves marrying one's brother's widow, the Kohen Gadol may not perform Yibum but must perform Chalitzah (see entry #2).
b) [line 12] MEYABEMIN (YIBUM)
(a) If a married man dies childless and has brothers who survive him, his widow (or widows) may not remarry until one of the deceased husband's brothers performs Yibum (levirate marriage) or Chalitzah (levirate release) with the widow (or one of the widows), as it states in Devarim 25:5-10. Chazal learn from the verses that if there are a number of brothers, there is a preference for the oldest brother to perform Yibum or Chalitzah (Yevamos 24a). If the conditions for the Mitzvah of Yibum do not exist, marital relations between a man and his brother's wife are prohibited and make them liable to the punishment of Kares.
(b) Yibum is a type of marriage. Unlike ordinary Kidushin, though, it can be accomplished only through Bi'ah and not through Kesef or Shtar (see Background to Kidushin 2:1:II:b). Nevertheless, the Rabanan instituted that one should precede Yibum with an act similar to Kidushei Kesef or Shtar, which is known as Ma'amar (see Background to Nedarim 74:4). The Bi'ah must be performed with the intention of fulfilling the Mitzvah.
(c) Since Yibum involves marrying one's brother's widow, the Kohen Gadol may not perform Yibum but must perform Chalitzah (see next entry).