Onan was Judah's second son by a Canaanite woman, Bath-shua. When his older brother Er died childless -- struck down by the LORD for his own wickedness -- Judah instructed Onan to fulfill the ancient custom of levirate marriage: to marry his brother's widow Tamar and raise up offspring in Er's name, so his brother's line and inheritance would not disappear (Genesis 38:6-8). Onan understood exactly what was at stake and refused it deliberately: "whenever he went in to his brother's wife, he wasted his seed on the ground, in order not to give offspring to his brother" (38:9). He accepted the privilege and standing of the marriage while withholding, by his own choice, the one obligation attached to it -- a calculated unwillingness dressed up as compliance. Scripture states plainly that "what he did was displeasing in the sight of the LORD, so He took his life also" (38:10), just as it had Er's. Onan's death left Tamar a childless widow twice over, setting up the story's next turn, in which she took matters into her own hands to secure an heir through Judah himself (38:12-30). Onan's account is one of Scripture's unflinching examples of judgment falling on calculated, selfish disobedience dressed in the appearance of duty.
Thought for Today
Onan accepted a duty's privileges while deliberately refusing its cost, and God judged his selfish deceit. Jesus, by contrast, held nothing back, giving Himself fully for us.
References: Genesis 38:4-9; Genesis 46:12; Numbers 26:19; 1 Chronicles 2:3
