Onan

Onan was the second son of Judah and a Canaanite woman named Shua, and the central figure of a morally complex episode in Genesis 38. After his older brother Er died childless, Judah instructed Onan to fulfill the duty of levirate marriage — to take Er's widow Tamar and raise up offspring to perpetuate his brother's name (Deuteronomy 25:5–6; Genesis 38:8). Onan, unwilling to produce an heir who would legally belong to his dead brother rather than to himself, deliberately prevented conception. The LORD regarded this as wicked and put him to death (Genesis 38:9–10).

The narrative's theological point is Onan's failure of covenant obligation — his refusal to perform levirate duty to preserve his brother's lineage — rather than a general prohibition. The episode is part of the larger providential story of how Judah's line was preserved through Tamar's unconventional persistence, leading eventually to the birth of Perez and the Davidic and messianic lineage.