Genesi 38:9

9 E Onan, sapendo che quella progenie non sarebbe sua, quando s’accostava alla moglie del suo fratello, faceva in modo d’impedire il concepimento, per non dar progenie al fratello.

Genesi 38:9 Meaning and Commentary

Genesis 38:9

And Onan knew that the seed should not be his
Should not be called a son of his, but a son of his brother Er; this is to be understood only of the firstborn; all the rest of the children born afterwards were reckoned the children of the real parent of them; this shows this was a custom in use in those times, and well known, and was not a peculiar case: and it came to pass, when he went in unto his brother's wife;
to cohabit with her, as man and wife, he having married her according to his father's direction: that he spilled [it] on the ground, lest he should give his seed to
his brother:
lest his brother's wife he had married should conceive by him, and bear a son that should be called his brother's, and inherit his estate; and this is the sin, which from him is called Onania, a sin condemned by the light of nature, as well as by the word of God, and very prejudicial to mankind, as well as displeasing to God, as follows:

Genesi 38:9 In-Context

7 Ma Er, primogenito di Giuda, era perverso agli occhi dell’Eterno, e l’Eterno lo fece morire.

8 Allora Giuda disse a Onan: "Va’ dalla moglie del tuo fratello, prenditela come cognato, e suscita una progenie al tuo fratello".

9 E Onan, sapendo che quella progenie non sarebbe sua, quando s’accostava alla moglie del suo fratello, faceva in modo d’impedire il concepimento, per non dar progenie al fratello.

10 Ciò ch’egli faceva dispiacque all’Eterno, il quale fece morire anche lui.

11 Allora Giuda disse a Tamar sua nuora: "Rimani vedova in casa di tuo padre, finché Scela, mio figliuolo, sia cresciuto". Perché diceva: "Badiamo che anch’egli non muoia come i suoi fratelli". E Tamar se ne andò, e dimorò in casa di suo padre.