וַיֵּ֣דַע אוֹנָ֔ן כִּ֛י לֹּ֥א ל֖וֹ יִהְיֶ֣ה הַזָּ֑רַע וְהָיָ֞ה אִם־בָּ֨א אֶל־אֵ֤שֶׁת אָחִיו֙ וְשִׁחֵ֣ת אַ֔רְצָה לְבִלְתִּ֥י נְתָן־זֶ֖רַע לְאָחִֽיו׃
E Onan sabia que a descendência não seria sua; e aconteceu que, quando ele ia à esposa de seu irmão, ele derramava [a semente] na terra, para não dar descendência ao seu irmão.
Ibn Ezra
They also claim that the phrase when brothers dwell together denotes close relatives, but not actual brothers. They bring the case of Boaz [cf. Ruth 3: 9 ; Ruth 3: 13] as evidence. This is vacuous, however, because no mention is made there of the word yibbum [here translated as “acting as the husband’s brother” — Translator], only of “redemption” [cf. Leviticus 25: 25]. Besides, what, then, is the meaning of the word together ? That they live in the same country? In the same courtyard? That they are fond of each other? The Dissenters claim further that the Scriptural usage of the term act as her husband’s brother proves that she is his brother’s wife in name only, but not in fact, as in the phrase “your brother’s wife has returned” [Ruth 1: 16]. But they have stumbled into error. Note that regarding the sons of Y ǝ hudah, Scripture explicitly says, “act as her husband’s brother” [Genesis 38: 8], although there he clearly already was her husband’s brother. Even the abovementioned use of the word “your brother’s wife” can be understood on the grounds that the two women were married to two brothers. Every sensible person knows that, although the prohibitions that were told to Moshe were not forbidden beforehand, if someone before the time of Moshe refrained from engaging in such actions he would not have displeased God . Scripture even states, “for the men of the land who preceded you practiced all these abominations” [Leviticus 18: 27], and yet we have no evidence that any prophet had ever admonished them against such actions. With respect to Onan Scripture specifically says that he did not “provide progeny for his brother” [Genesis 38: 9] and consequently “it was evil in the sight of God ” [Genesis 38: 10]. For these reasons, we will rely on the tradition that actual brothers are meant here.
Rav Hirsch
Überlebt ihn nämlich ein möglichst nächster, unter denselben Zeiteinflüssen atmender Blutsverwandter – als solcher steht nur ein von demselben Vater erzeugter, mit ihm zugleich lebender, nicht nachgeborener Bruder da – so tritt an diesen die Anforderung hinan, die Ehe seines hingeschiedenen Bruders mit dessen hinterlassenen Witwe im Sinne des יבום, d. h. im Sinne des Fortbaus des unvollendet gebliebenen Hauses des Verstorbenen, fortzusetzen und zu diesem Zwecke mit der Übernahme der Witwe zugleich als Vollerbe der materiellen Hinterlassenschaft des Verstorbenen einzutreten. Über dieser Ehe, die nur als Fortsetzung der Ehe des Verstorbenen zu begreifen ist – und daher nach ursprünglichem Gesetze nicht nochmaliger קידושין bedarf – sowie über dem damit zugleich angetretenen Erbe bleibt der Name des Verstorbenen im Geiste schweben, dem damit die Möglichkeit eines geistig und sittlich fortwirkenden Einflusses in einer solchen in seinem Namen und im Sinne seines fortzuerhaltenden Andenkens geschlossenen Ehe und deren Folgen eröffnet bleibt; ein Einfluss, der doch muss so wirksam sein können, daß das Bewusstsein davon – ויד כי לא לו יהיה הזרע (Bereschit 38, 9) – einen schlechten Bruder in nichtswürdiger Engherzigkeit zur Schlechtigkeit vor Gott hinreißen konnte. —
Ramban
AND ER, JUDAH’s FIRSTBORN, WAS WICKED IN THE SIGHT OF THE ETERNAL. Scripture does not specify the nature of his wickedness as it did in the case of his brother.148Verse 9 here. Instead, it simply states that he died for his own sin. It informs us that this was not by way of punishment of Judah for his role in the sale of Joseph, since the saving of Joseph’s life by Judah compensated for his role in the sale. There was no case of death of a child in the house of the patriarchs except this one who was wicked in the sight of the Eternal, since the race of the righteous is blessed. This is why Jacob mourned many days for his son Joseph, and he refused to comfort himself,149Above, 37:34-35. for he considered this to be a great punishment to himself, quite apart from his love for him.