Genesis 38:7-9

Wycliffe Bible

⁷ And Er, the first begotten son of Judah, was wayward in the sight of the Lord, and therefore he was slain of the Lord (and so the Lord killed him).

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;)