Genesis 38:8-10

Wycliffe Bible

⁸ Therefore Judah said to Onan, his son, Enter thou [in] to the wife of thy brother, and be thou fellowshipped to her, that thou raise seed to thy brother. (And so Judah said to his son Onan, Sleep with thy brother’s wife, and be fellowshipped to her, and so raise thou up seed, or some sons, for thy brother.)

⁹ And he knew that sons should not be born to him; and he entered [in] to the wife of his brother, and shedded his seed into the earth, lest the free children should be born by the name of the dead brother; (But Onan knew that any sons who would be born would not be his; so he slept with his brother’s wife, but he poured out his seed onto the ground, so that no children would be born in the name of his dead brother;)

¹⁰ and therefore the Lord smote him (and so the Lord struck him down), for he did (an) abominable thing.