Génesis 38:9

9 Y Onán sabía que la descendencia no sería suya; y acontecía que cuando se llegaba a la mujer de su hermano, derramaba su semen en tierra para no dar descendencia a su hermano.

Génesis 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:

Génesis 38:9 In-Context

7 Pero Er, primogénito de Judá, era malvado ante los ojos del SEÑOR, y el SEÑOR le quitó la vida.

8 Entonces Judá dijo a Onán: Llégate a la mujer de tu hermano, y cumple con ella tu deber como cuñado, y levanta descendencia a tu hermano.

9 Y Onán sabía que la descendencia no sería suya; y acontecía que cuando se llegaba a la mujer de su hermano, derramaba su semen en tierra para no dar descendencia a su hermano.

10 Pero lo que hacía era malo ante los ojos del SEÑOR; y también a él le quitó la vida.

11 Entonces Judá dijo a su nuera Tamar: Quédate viuda en casa de tu padre hasta que crezca mi hijo Sela; pues pensaba: Temo que él muera también como sus hermanos. Así que Tamar se fue y se quedó en casa de su padre.