Onan’s story is understandably baffling to many readers today. The second son of Judah, Onan appears in a strange account, one that serves as an interlude to the tale of Joseph.
Onan’s older brother, Er, had been deemed guilty of an unspecified offense perhaps idolatry, a distinct possibility, since Onan and Er’s father had married a Canaanite. In any case, Er’s sin led God to strike him down, after which Judah ordered Onan to sleep with Er’s widow.
What seems like such an inappropriate command today was rather customary in the ancient Near East. The practice, known as levirate marriage, would later be enshrined in the Law of Moses (see Deuteronomy 25:5–6).
When a husband died leaving no heir, the dead man’s brother was to take the widow as his own wife, with the aim of providing an offspring. There was just one catch: The firstborn son would be regarded as the offspring of the deceased brother, not the one who married his widow.
As a result, the dead brother’s name would endure, and his inheritance would pass to the child who was regarded as his own. The system was also designed to afford some protection to widows, who were quite vulnerable in the ancient Near East. With the inheritance that passed to the offspring of such marriages, widows could be provided for in the years to come.
Onan found that the prospect of a son who would not be his own was more than he could bear. So he refused to sleep with Er’s widow in a way that would allow a child to be conceived—and, more important, no heir would be produced to claim Er’s inheritance. God was furious with Onan and his utter disregard for justice. Like his brother before him, Onan was struck down by God.
Onan’s name means “vigorous”—perhaps an ironic wordplay. A man whose stamina and vigor should have easily helped produce children for Er’s widow had instead refused his God-given responsibility. In the end, Onan lost not only his vigor but his life, too.