Our parashah contains the first recorded incident of one of the most intriguing Mitzvos, Yibum (levirate marriage). When Yehudah’s firstborn Er died without progeny, he instructed his second son, Onan, to marry the widow, Tamar in fulfillment of Yibum. When Onan, too, died childless, and Tamar saw that Yehudah was not instructing his third son, Shelah, to perform Yibum, she took matters into her own hands and tricked Yehudah into doing so (Bereishis ch. 38).

In truth, the Mitzvah of Yibum was only given to the Jewish people centuries later at Sinai, and even then, the Mitzvah would be exclusively allocated to the brother of the deceased, such as Onan or Shelah, and not any other relative, even the father of the deceased, such as Yehudah. Henceforth from the Giving of the Torah, it is a severe sin for someone to marry the widow of his deceased son, and even the widow of his deceased brother, in circumstances where Yibum does not apply. The above incident can only be understood in light of the idea that the Patriarchs began keeping the Torah voluntarily even before it was given at Sinai, according to their understanding and with flexible application of the laws to accommodate the circumstances. Therefore, as long as the union did not involve incest, any family members could choose to perform the Mitzvah, though preference would be given to brothers to fulfill the Mitzvah completely. It is remarkable that the union between Yehudah and his son's widow, which was regarded then as a Mitzvah, would have been regarded as a severe sin had it occurred after the Giving of the Torah (Shir HaShirim Rabbah 1:16, Ramban,and Malbim).

According to one view, even after the Giving of the Torah, the concept of the Mitzvah remained applicable to extended family members in a case where there is no surviving brother, as long the union does not involve incest. It was in this limited sense that Boaz performed Yibum by marrying his great-nephew Machlon’s widow, Rus. For a discussion about this incident and about Yibum in general, see Divros Tzvi (Yevamos §1-§4); this excellent work provided some of the sources of this article.

We will summarize some of the practical details of Yibum and Chalitzah, and then we will explore their meaning. A brother is only commanded to perform Yibum if he is capable of having children. After performing Yibum, he inherits the deceased brother’s possessions. If he does not want to perform Yibum, the Torah gives him the option of performing Chalitzah instead. Even if he wants to perform Yibum, if the Beis Din determines the marriage to be practically inappropriate, such as if there is a great age gap between him and the widow, the Torah instructs the Beis Din to advise for the alternative of Chalitzah. In most cases, however, Yibum is the ideal choice for the living brother, and only if he chooses not to forego the fulfillment of this great Mitzvah does the Torah give him the option of Chalitzah, which is considered to be a lesser Mitzvah. It is a public ritual in which the widow removes the living brother’s sandal and spits on the ground in front of him.

We will present a selection of the ideas behind this Mitzvah on two levels of understanding: the basic level and the esoteric level. On the basic level, Yibum may be understood as a means to grant continuity to a man who dies without progeny. When a brother, who is born of the same father, marries the widow of the deceased and inherits his house and possessions, and only because the deceased married without having children, the progeny that emerges from the Yibum union becomes known as the progeny of the deceased (Toldos Yitzchak and Maharal). This may be further understood in light of the idea that a husband and wife are considered one entity (Bereishis 2:24). In this sense, the deceased lives on in his wife, and the children she has from her husband’s “substitute” may be regarded as the children of the deceased, and the merits earned by those children and their line of progeny for all generations will be linked to the soul of the deceased (Sefer HaChinuch). It is therefore an act of eternal kindness for the living brother to marry the widow, so much so that Hashem regards him as if he partnered in the creation of the world (Zohar Chadash, Rus). It is also an act of kindness for the widow, who might otherwise be left without a husband, without children, and without a means of livelihood (Shai LaMorah to Moreh Nevuchim 3:49). This seems to have been a primary consideration behind Boaz’s decision to perform Yibum with Rus, a penniless convert. Nevertheless, with the lessening of the nation’s spiritual caliber over the generations, many people were no longer performing this Mitzvah for the sake of Heaven, and the Sages enacted that the alternate option of Chalitzah be followed instead.

As noted, Chalitzah involves the widow’s spitting in front of the living brother. The Midrash (Tanchuma, Mishpatim §7) calls this a chok, a Divinely ordained decree without an apparent logical basis, but the Commentators nevertheless shed light on its meaning. Some explain that it is an expression of disgust over the living brother’s refusal to grant continuity to the soul of his deceased brother (Recaniti). The putrid drop of spit is also meant to resemble the living brother's seed that was meant to grant continuity to the deceased brother's soul. Thus, the spitting implies that the living brother has foolishly substituted eternal kindness for eternal disgrace (Hilchos Gedolos, cited in Sifsei Kohen). She removes his sandal to indicate that until now, his brother was not truly dead, for his soul still had hope for continuity, and now that the living brother has effectively eliminated that hope, he ought to stand barefoot in mourning over his brother’s loss (Rabbeinu Bechaye). Generally, the removal of a sandal is an intricate task that includes the unwinding of straps, which a person sometimes accomplishes with the assistance of his wife. Thus, the widow’s removal of the sandal adds disgrace to the living brother, for she implies that had he agreed to grant continuity to his brother through Yibum, she would have become his wife, and now, all the involved parties have lost out (see also Rashbam).

To summarize, on the basic level, we may understand Yibum as an act of kindness and a beneficial societal arrangement. In the event that a brother refuses to comply, Hashem does not force him to do so, but rather indicates His disapproval by means of the ritual of Chalitzah.

On the esoteric level, which we will examine from afar and describe in general terms, the soul of the deceased becomes reincarnated in the product of the Yibum union. For example, according to one view, Er and Onan became reincarnated in Tamar’s twins, Peretz and Zerach, and so too, Machlon became reincarnated in Rus's son, Oved. The reincarnation of these souls was particularly important because they were links in the chain of generations that led to King David, and eventually to Mashiach. The soul of the childless deceased brother remains within the widow and then emerges into her son through Yibum with the living brother because the souls of brothers are closely related (see Recaniti to Bereishis 38:8 and Yahel Ohr, Vol. 1, 28a).

In the event that the living brother does not want to perform Yibum, the widow may release the soul of the deceased from her by means of Chalitzah. The freeing of the living brother’s foot from the sandal alludes to the freeing of the soul of the deceased from the widow. The soul must then wait for its rectification through other means, such as through the merit of a great Torah scholar (Yahel Ohr, ibid).