And what he did was wicked in the sight of the LORD, and he put him to death also.
This is the second death in Judah's family, and Genesis marks it with the name "the LORD." Two questions follow. What was so evil in what Onan did? And why does this dark story sit inside the family line that leads to the Messiah?
Onan's Real Sin
The act described in verse 9 was not the whole offence. Onan took the marriage and refused the duty that came with it.
Edwin N. CrossOnan married Tamar, but then refused to grant her the privilege of being the mother of Judah's heir. He was prepared to marry her and enjoy relations with her, but he wanted to hold back his strength. In Onan's case, the sin that so displeases God was not simply spilling his seed on the ground. It was selfishness. He wanted her to stay a childless and despised widow, and that desire drove everything he did. It was not a single sin but a repeated one, for the word "when" in verse 9 should read "whenever."
Another writer frames it as an agreement made and then broken:
L. M. GrantHe did not keep his side of the agreement, and the Lord considered this serious enough to kill him too. The reason was his complete selfishness: the child would not count as his own, even though it really would be.
The Name Used Here
Which name for God the text uses matters here. Genesis does not simply say "God." It uses "the LORD" — Jehovah.
J. N. DarbyIn the rest of the book, the name "Jehovah" is used in only a few places. One is Judah's case, chapter 38:7-10, where you can see that these are His own special ways and His government. Another is Joseph sold and in trial, chapter 39. Another is after Dan, where Jacob waits for His salvation, chapter 49:18 — the longing of an Israelite for the coming kingdom.
So this death is not bad luck. It is God dealing with Judah's house in His own government.
A House That Broke Down
Onan's death is the second in a row. Judah watched his own household fall apart under God's hand.
An Outline of Sound WordsJudah could have cried out, "My house is not so with God!" Er, his firstborn, "was wicked in the sight of the LORD, and the LORD put him to death." Then Onan, his second son, rebelled against his father's command, and the Lord killed him too.
Judah had married into Canaan, and the results showed in his sons.
William KellyJudah was to be the leading royal tribe and the ancestor of the King of kings. Yet he shamelessly takes a daughter of Canaan for himself. No wonder that wickedness killed his firstborn, and disgrace killed his brother.
What the Three Names Suggest
Some writers find meaning in the names of Judah's three sons. They read the loss of the first two as a picture of God's dealings with the nation.
Frederick W. GrantJudah's line still continues on the earth, even though God's wrath is on the first two sons. Their names speak of "enmity" (Er) and "iniquity" (Onan). But the third son, Shelah ("sprout"?), speaks of divine power in resurrection, bringing life out of death. In this way God preserves a remnant.
The text itself does not give these meanings. Commentators offer them as a suggestion.
Judgment That Does Not End the Line
This chapter is one of the ugliest in Genesis, yet God does not abandon Judah. The same story that records two deaths also carries the line that leads to Christ.
William KellyYet from this guilty Judah, and from Tamar, came the One who cleanses from all sin by His blood. He will reign over the universe to God's glory. That reign goes far beyond all that Joseph pictured, just as He went far lower in humiliation and suffering.
God's answer to this chapter is not to cover it up.
Frederick W. GrantTamar's name appears in the Lord's genealogy in the gospel of Matthew. Her sin alone brought her there, and God has taken pains to record this striking fact — and to record it twice. In the same way, simply as sinners, we have the right to rejoice in a work done for the need of sinners.
Summary
- Selfishness — the sin was not one physical act. It was a settled refusal to give his brother an heir, repeated every time. Verse 9 means "whenever," not "once."
- Seen — the name "the LORD" marks this death. It shows God's own ways and His government at work in Judah's house.
- Sown — Judah married into Canaan, and he reaped the harvest in his sons. What the father allowed, the next generation acted out.
- Spared — two sons are gone, but a third remains. Some read Shelah's name as "sprout": a remnant brought out of death.
- Saved — the line God judged is the line God kept. Tamar's name stands in Christ's genealogy, and it was her sin that brought her there.