Was Onan turning Yibum into Arayot?

Question

There are many commentators that invoke the story of Onan as a source for the prohibition behind onanism, but there seems to be a distinctly different issue going on that is "evil in the eyes of Hashem."

Ordinarily, the former wife of your brother through widowhood would be expressly forbidden. It is only due to the positive mitzvah of yibum that the kum aseh is docheh the lo sa'aseh because we are commanded "lehakim zera le'achiv." Onan engaged in the "act" of yibum, yet it is expressly stated in the Torah that he engaged in coitus interruptus because he refused to fulfill this positive command. As such, he was not fulfilling the kum aseh and therefore there would BE no heter for him. Thus, Onan wasn't engaged in masturbation, but in an act of gilui arayos with eishes ach!

We find later in the Talmud that some Chachomim decreed that because we are concerned with the "purity of the intent" behind the act they prefer chalitzah over yibum, though this is one of the many splits between Asheknazim (following Rabbeinu Tam) and Sephardim (following Rambam). This would appear to directly mirror the incident with Onan.

Is there a source that interprets Onan's behavior in this manner - as a violation of gilui arayos due to his refusal to fulfill the heter of yibum?

Answer 1

The basic answer to your question appears to be no. The meforshim do not connect the actions of Onan to aishes ach. One reason is that they explain the pesaukim as showing that both Er and Onan did the same aveirah. Thus, Er could not have been involved with aishes ach. Additionally, the discussion of Chazal about preferring chalitza rather than yibum does not invalidate the yibum. It is a matter of hashkafa. however, if the yibum had been done, it was valid and the isur of aishes ach does not apply.

Rashi points out that Er also deliberately refused to allow Tamar to become pregnant. This refusal to fulfill the mitzvah of pru u'rvu is what caused Hashem to punish him. Rav Hirsch connects this with the mitzvah of Pru U'Rvu

was evil in the eyes of the Lord: [His evil was] like the evil of Onan, viz. that he wasted his semen, as it is written in connection with Onan: “and He put him to death also,” meaning that, as Er’s death, so was Onan’s death. Now, why should Er waste his semen? So that she (Tamar) would not become pregnant and her beauty be impaired. [From Yev. 34b]

Onan committed the same sin (though for a different reason). That is, since any children that they might have would be called "children of Er", he refused to allow her to become pregnant. The first born child is treated as the child of the deceased brother. Thus, the child would have been treated as the heir of Er and not of Onana.

and raise up progeny: The son shall be called by the name of the deceased. [From Targum Jonathan ben Uzziel]

he wasted [his semen] on the ground: He practiced coitus interruptus. [From Gen. Rabbah 85:5]

Yibum and Chalitzah

The Torah dictates that if a married man dies childless, the widow is to marry her dead husband's brother, preferably the eldest. The firstborn son they produce together is considered a continuation of the dead husband's line.