Komentarz do Rodzaju 38:9

ושחת ארצה AND HE DESTROYED ONTO THE GROUND — He 'threshed inside and winnowed outside' (Genesis Rabbah 85:5).

כי לא לו יהיה הזרע, people in those days were extremely fussy about this point.

כי לא לו יהיה הזרע, he knew that not he alone would get the credit for performing this act of love for his deceased brother, seeing that part of the merit would go to his older brother seeing he had first fulfilled the commandment of marrying, so that he would share in the merit of having a son sired posthumously through a levirate union with his widow by his younger brother. [I fail to understand how someone who married in order to use sex only as an act of self-gratification can be described as having acquired a merit by the act of marrying. Perhaps gratifying the sex urge only with someone to whom one is married is by itself a מצוה, and this is what Seforno had in mind. Ed.]

וידע אונן, he realised this only when his father said to him that it was his task to see that his brother’s seed would be perpetuated.

וידע אונן, “Onan realised;” [the author’s problem with this expression is that the term ידע, normally refers to something in the past which was known as a fact. Ed.] The author quotes הידוע נדע, “how were we to know,” in Genesis 43,7 as proof that the term can also be used here.

נתן זרע, the vowel kametz here is in fact a chataf kametz, as every word spelled plene, i.e. with the vowel cholem as the letter ו when it appears in construct form such as here has this vowel shortened to a chataf kametz. The result is that the stress will be on the on the last syllable, whereas the word following immediately afterwards will have its stress on the first syllable. In effect this makes the words נתן זרע in our verse as if they had been connected by the hyphen, makkif. Other examples of similar constructions are Psalms 145,8 ארך אפים וגדל חסד [where the word גדל is a shortened version of גדול with the ו as the vowel cholem. Ed.] Another example is found in Exodus 21,11 ואם שלש אלה לא יעשה לה, “if he will do none of these three things for her, etc.” Yet another such construction is found in Numbers 35,14 אבל את שלש הערים, “however the three cities, etc.”

לבלתי נתן זרע לאחיו, for not having given his seed for the use (perpetuation on earth) of his deceased brother.

ושחת ארצה, he ejaculated outside her vagina, just as we explained in connection with Er.

כי לא לו יהיה הזרע, “for the child would not be named after him;” according to the plain meaning of the text, זרע is used with the production of a crop in the field, not a human being.'והיה אם בא וגו, “and whenever he would engage in marital relations, etc;” he reasoned that if he were to impregnate his wife (the widow of his brother) the result would be that he would at the same time destroy his own ancestral share of the land. For who would then do the plowing and all the other work needed to be performed in the field?

לבלתי נתן זרע לאחיו, “not to provide semen for his brother;” we find similar considerations in the Book of Ruth 4,6 when a potential redeemer declined to perform a levirate marriage with Ruth;” [as the latter had not been a Jewess, and a Moabite even, his consideration was not sinful. Ed.] Besides, there was another redeemer willing and anxious to perform such a ritual for her.