Genesis 38:2-10

2There Judah saw the daughter of a Canaanite man whose name was Shua, and he took her as wife and slept with her.

3Then she became pregnant and gave birth to a son, and he named him Er.

4She became pregnant again and gave birth to a son, and she named him Onan.

5She gave birth to yet another son and she called him Shelah. He was in Chezib when she gave birth to him.

6Then Judah got a wife for Er, his firstborn, and her name was Tamar.

7But Er, Judah’s firstborn, was evil in Adonai’s eyes, so Adonai put him to death.

8Then Judah said to Onan, go to your brother’s wife to perform the duty of a brother-in-law to her, and raise up a seed for your brother.

9But Onan knew that the seed would not be his. So every time he went to his brother’s wife he would destroy it on the ground so as not to provide a seed for his brother.

10What he did was evil in Adonai’s eyes, so He put him to death also.