Then she conceived again and gave birth to a son and named him Onan.

Then Judah told Onan, “Go in to your brother’s widow, and perform your duty as a brother-in-law [under the levirate marriage custom]; [be her husband and] raise children for [the name of] your brother.”

Onan knew that the child (heir) would not be his [but his dead brother’s]; so whenever he lay with his brother’s widow, he spilled his seed on the ground [to prevent conception], so that he would not give a child to his brother.

The sons of Judah: Er, Onan, Shelah, Perez, and Zerah—but Er and Onan died in the land of Canaan. And the sons of Perez were Hezron and Hamul.