Genesis 38:6

3 And she conceiveth, and beareth a son, and he calleth his name Er;

4 and she conceiveth again, and beareth a son, and calleth his name Onan;

5 and she addeth again, and beareth a son, and calleth his name Shelah; and he was in Chezib in her bearing him.

6 And Judah taketh a wife for Er, his first-born, and her name [is] Tamar;

7 and Er, Judah`s first-born, is evil in the eyes of Jehovah, and Jehovah doth put him to death.

8 And Judah saith to Onan, `Go in unto the wife of thy brother, and marry her, and raise up seed to thy brother;`

9 and Onan knoweth that the seed is not [reckoned] his; and it hath come to pass, if he hath gone in unto his brother`s wife, that he hath destroyed [it] to the earth, so as not to give seed to his brother;