Genesis 38:7-9

Revised Geneva Translation

⁷ Now, Er, the firstborn of Judah, was wicked in the sight of the LORD. Therefore, the LORD killed him.

⁸ And Judah said to Onan, “Go into your brother’s wife and do the office of a kinsman to her; and raise up seed to your brother.”

⁹ And Onan knew that the seed would not be his. Therefore, when he went in to his brother’s wife, he spilled it on the ground, lest he should give seed to his brother.