On this daf, we find some of the halachos of chalitzah.
A certain woman was happily married until tragedy struck and her husband died suddenly. Since they had no children, it appeared as though the widow would require chalitzah from her deceased husband’s only brother. Unfortunately, the yovom was a mumar.
Both Rav Nachshon Gaon and Rav Yehudai Gaon ruled that the wife is free to marry whomever she wants without chalitzah from the mumar. They reasoned that just as it is permitted to lend money with interest to a mumar because lending money with interest is only prohibited to one’s spiritual brother, one’s brother in observing Torah and mitzvos, the same is true regarding the mitzvah of yibum. This mitzvah is only with a spiritual brother who observes Torah and mitzvos, not a mumar. And even if the mumar subsequently does teshuvah, he is still potur from yibum and chalitzah. This is learned from the Gemara in Yevamos 111, which states that a yevamah who may not do yibum is like the widow of a brother who had children and is thenceforth forbidden to do yibum. Since the repentant mumar couldn’t do yibum at the time that his brother died because he was not a spiritual brother to his own biological sibling, even if he repented later he cannot do yibum subsequently.
The Terumas Hadeshen completely opposed this psak, stating, “There is an essential difference between the word brother used in the context of the prohibition against lending with interest and the commandment to give charity, and the word brother used with regards to yibum. The word brother in connection with ribbis and tzedakah connotes achvah—any fellow Jew with whom one shares a spiritual bond of loving communion—since it certainly doesn’t mean to apply these mitzvos only to one’s biological brother. Therefore, the word brother in these contexts alludes to a person who should be treated with achvah – namely, one who is your brother in observing Torah and mitzvos. In the context of the mitzvah of yibum, however, the word brother does indeed refer to one’s biological brother. Therefore, there is an obligation to perform yibum regardless of the brother’s spiritual level.
The Terumas Hadeshen concluded, “The proof of this is in Eisav. Although he was a rasha merusha, the Torah still refers to him numerous times as the brother of Yaakov” (Terumas Hadeshen).