פירוש על יבמות 4:11

ארבעה אחים וכו' – and the same law applies even also with many wives, if it is possible to support them, permission is in his bands to marry all of them, and the fact that it (i.e., the Mishnah) took four is good advice: for it comes to teach us, for yes, more than that, no, for just as the duty of marital visits at certain intervals arrives during the month.

Introduction Our mishnah teaches that one yavam can perform yibbum for several women if they were widows of different brothers. However, if they were all from the same brother he can have yibbum with only one of them.

ביאתה או חליצתה פוטרת צרתה – and he doesn’t perform levirate marriage with both of them, as it is written (Deuteronomy 25:9): “who will not build up his brother’s house.” One house he builds, but he does not build up two houses. And he doesn’t perform Halitzah with both of them, and whomever does not come up for levirate marrae does not come up for Halitzah, for since that both of them like each other do not go up for lievirate marriage, as we stated, he builds one house,” so also, they don’t go up for Halitzah.

If four brothers were married to four women, and they died, if the eldest [surviving brother] desires he may contract yibbum with all of them. In this case four widows from four different brothers all fall before the same brother for yibbum or halitzah. The mishnah teaches that this one yavam may have yibbum with all of them. The Talmud, however, notes a certain reservation. He is allowed to do so only if he is going to be able to provide well for them all. Bigamy was permitted under Jewish law, but only on the condition that the husband provide equally well for each wife. Also, the Talmud notes that it is not such a good idea to have four wives for there will be much strife in his home. Nevertheless, it is theoretically possible.

חולץ לפסולה – and he will not disqualify that [woman who is] fit [to marry into] the priesthood, for a woman who has undergone Halitzah is disqualified from the priesthood, and a man should not empty the waters of his cistern and others need it.

If a man was married to two women and died, sexual relations or halitzah with one of them exempts her rival. If two women who were married to the same brother fall in front of the yavam for yibbum, he need perform halitzah or yibbum for only one of them. He is not allowed to have yibbum nor halitzah with both.

If one of them was eligible [to marry a priest] and one ineligible [to marry a priest], then if he performs halitzah it should be to her who is ineligible, and if he contracts yibbum it may be with her who is eligible. If one of these two women was already ineligible to subsequently marry a kohen, for instance she was a divorcee from a previous marriage, the yavam should do halitzah with her and not with the other sister. This is because halitzah makes her forbidden to subsequently marry a kohen and there is no reason to needlessly disqualify the eligible widow from marrying a kohen. However, if he is going to do yibbum, he can have yibbum even with the sister eligible to the kohen, since this does not disqualify her from later marrying a priest.