Onan

Onan was a figure detailed in the Book of Genesis chapter 38, as the second son of Judah who married the daughter of Shuah the Canaanite. Onan had an older brother Er and a younger brother, Shelah, as well.

Onan was commanded by his father, Judah, to perform his duty as a husband's brother according to the custom of levirate marriage with Er's widow Tamar. Onan refused to perform his duty as a levirate and instead "spilled his seed on the ground whenever he went in" because "the offspring would not be his", and was thus put to death by Yahweh. This act is detailed as retribution for being "displeasing in the sight of Lord". Onan's crime is often misinterpreted as being masturbation, but it is universally agreed among biblical scholars that Onan's death is attributed to his refusal to fulfill his obligation of levirate marriage with Tamar by committing coitus interruptus.

Biblical account

After Yahweh slew Onan's oldest brother Er, Onan's father Judah told him to fulfill his duty as a brother-in-law by entering into a levirate marriage with his brother's widow Tamar to give her offspring. Religion professor Tikva Frymer-Kensky has pointed out the economic repercussions of a levirate marriage: any son born to Tamar would be deemed the heir of the deceased Er and could claim the firstborn's double share of an inheritance. However, if Er were childless or only had daughters, Onan would have inherited as the oldest surviving son.