Timothy S. Morton
No discussion of the biblical seed would be complete without examining the account of Judah, Tamar, and Onan as found in Genesis chapter 38. First, lets look at the passage,
2 And Judah saw there a daughter of a certain Canaanite, whose name was Shuah; and he took her, and went in unto her.
3 And she conceived, and bare a son; and he called his name Er.
4 And she conceived again, and bare a son; and she called his name Onan.
5 And she yet again conceived, and bare a son; and called his name Shelah: and he was at Chezib, when she bare him.
6 And Judah took a wife for Er his firstborn, whose name was Tamar.
7 And Er, Judah's firstborn, was wicked in the sight of the LORD; and the LORD slew him.
8 And Judah said unto Onan, Go in unto thy brother's wife, and marry her, and raise up seed to thy brother.
9 And Onan knew that the seed should not be his; and it came to pass, when he went in unto his brother's wife, that he spilled it on the ground, lest that he should give seed to his brother.
10 And the thing which he did displeased the LORD: wherefore he slew him also.
Judah, Jacob's (or Israel's) son found him a Cannaanite woman for a wife and she had three sons by him, Er, Onan, and Shelah. When Er was old enough, Judah "took a wife" for him to marry. This is an example of an arranged marriage; where one's spouse is picked by someone else, usually the father. This is actually a type of espousal or betrothal. Judah picked his son's wife and set up the marriage. That is why it says "he took a wife." Tamar actually became Er's "wife" when Judah made the formal arrangement with her father (vs. 11) much like Joseph and Mary were "husband and wife" before they actually came together in marriage (Matt 1:).
The terms "husband" and "wife" refer to a contractual arrangement or mutual agreement. The term "marriage" in essence refers to a man and woman coming together as "one flesh." It is possible for a couple to be husband and wife before they are actually married. For more on this, see our work From Marriage To Remarriage.
Genesis 38:7 then tells us that Er was "wicked in the sight of the Lord" and "the Lord slew him." Er didn't seem to last long at all after his marriage arrangement. What Er did is unknown, but since the context of this passage is Judah's descendants or "seed," that may have something to do with it.
With verse 8 things get more interesting. Judah tells his next son, Onan, "Go in unto thy brother's wife, and marry her, and raise up seed to thy brother." With these few words several things are revealed. First, Judah is still taking charge of his son's lives (they were likely only teenagers), and he tells Onan to marry his brothers "wife." This kind of practice is known as Levirate Marriage. It is a "type of marriage in which the brother of a deceased man is obliged to marry his brother's widow." The Lord even directed the Israelites to practice this a few centuries later in Deuteronomy 25:
5, If brethren dwell together, and one of them die, and have no child, the wife of the dead shall not marry without unto a stranger: her husband's brother shall go in unto her, and take her to him to wife, and perform the duty of an husband's brother unto her.
6, And it shall be, that the firstborn which she beareth shall succeed in the name of his brother which is dead, that his name be not put out of Israel.
Since the Hebrews of Judah's time practiced it, Levirate Marriage must have been an ancient custom that may have went all the way back to Babel or even earlier. Later on with Moses the Lord "codified" the practice with specific details. It shows the huge importance the people put on their seed, descendants, heritage, and bloodline. They wanted to protect a male's name from being forgotten, especially a firstborn son. The Lord considered these arrangements so important that they superseded the standard law of a man NOT being permitted to marry his brother's widow (Leviticus 18:16; 10:21)
Another fact revealed in verse 8 is the people at that time understood that it took male and female sexual union for children to be conceived. The reader may be thinking, "Duh...doesn't everybody know that?" No, they don't. There are even cultures today who don't believe it. Judah knew that his son would have to give his "seed" to the "wife" for her to conceive his child. Since his firstborn, Er, was now dead, Judah wanted to preserve his name by Onan having sexual relations with Tamar as a proxy of Er and then giving the first born son Er's name.
The third fact mentioned is a clear definition of the "act of marriage." The words "Go in unto thy brother's wife, and marry her" leave no doubt. Onan would marry Tamar with the act of going "in unto her" (a euphemism for sexual intercourse, like "know"). No preacher, no ceremony, no piece of paper. The "going in" was the marrying.
Notice also how even though Er is dead, Tamar is still called his "wife." Romans 7:2 says "...but if the husband be dead, she is loosed from the law of her husband" showing that death dissolves a marriage, but in special cases like Levirate Marriage, the woman is still in a sense the dead brother's wife because if things work out with a living brother, she will be raising the dead husband's legal son.
In Verse 9 it all comes to a head. Onan understood if he does what his daddy said the first born son that may come about will legally be his brother's and "should not be his." And more than that, that son, which is his, but not his, will inherit all the inheritance due to his legal dad, Er! The boy would get a double portion of Judah's estate because Er was his firstborn son! We learn about how inheritance arrangements can cause envy and deception by reading what happened to Onan's grand-daddy Jacob and his barely older twin brother, Esau (Gen 25-27).
So even though he may have been quite young, Onan understood the inheritance ramifications with him giving seed to his brother. If he did not give seed to Tamar, he, being the next living son of Judah, would himself inherit all the firstborn privileges. But if Tamar would have a male child by him, Onan would only inherit a regular portion of inheritance.
Nevertheless, to not disappoint his daddy (and maybe also because he thought his sister-in-law was "hot." Remember, she was hand-picked by Judah for his firstborn son. Most likely he would pick the handsomest and most comely "daughter" he could get.), Onan agreed to the special marriage with Tamar...but he secretly had a devious scheme in mind.
Eventually, Onan was officially given to Tamar, and he "went in" to her to consummate the marriage. But Onan was a "clever guy." He had learned from his daddy that children can only come about when the "seed" (semen) passes from him to Tamar, so he figured he would sexually join with Tamar and consummate the union but when he deemed the seed was ready to pass to her, he would interrupt the union and "spill his seed on the ground." That way almost everyone would be satisfied. His daddy would be happy Onan was "trying." Onan himself would be happy getting to have all this "fun" with his hot sister-in-law; and Onan also would be really happy he was not giving up the extra inheritance he would get to keep if Tamar doesn't have a male child. Since these things normally take place "behind closed doors," the only other person who would know what he was doing would be Tamar, but maybe he thought she didn't know as much about the "birds and the bees" as he did or perhaps he thought he could show her such a "good time" she wouldn't care.
Ah, the naivety and stupidity of youth. Here is an enhanced, but possible, account of what happened,
Onan went in unto Tamar, had his measure of fun, but refused to "finish the job." He let it finish on the dirt floor of the tent. Onan wrapped his cloak around himself, swaggered out the tent door with a smile on his face, and said to Judah, "I did it, Daddy...I did it...I did it real good."
Judah puts his hand on his boy's shoulder and says, "Good job, son. I knew you could do it. Now your brother can have an heir." All the while Tamar was standing at the door of the tent wrapped only with a sheepskin, gently shaking her head at what she overheard.
Onan walks from his daddy over to a tree he frequently sit under and congratulates himself for how well his plans had gone, and high in the tree a rotten limb breaks loose, hits Onan on the skull, and kills him on the spot.
Onan forgot there was someone else who was privy to his scheme besides Tamar: the God of his fathers Abraham, Isaac, and Jacob. This God made promises to Abraham concerning his seed and has plans to make an even more specific promise to Onan's daddy, Judah, concerning His own Son that will eventually come through him. The Lord will not tolerate any upstart like Onan making light of it.
For centuries, if not millennia, men have debated about the "sin of Onan." In recent times many ministers of the Victorian era taught Onan'a sin was masturbation. They even named the act after Onan with "Onanism." However, an unbiased reading of the passage shows self-stimulation was not the actual sin, even if it did happen at the end. The account is clear in stating that he went in unto Tamar. The very thing Judah told him to do. So Onan did have intercourse with her, he just withdrew before his seed could be passed. The fancy term for this is coitus interruptus.
The real sin of Onan was his selfish refusal to sire a son through his sister-in-law. His motives for this refusal are not mentioned, but besides the aforementioned inheritance issues, there may have been others. Maybe he and Er didn't get along; maybe he was jealous and didn't want to help him, etc. The words in vs. 9 may indicate that ("...lest that he should give seed to his brother."). The reason, though, doesn't really matter. He just refused to do something his father insisted was his obligation to do.
There is another aspect to Onan's behavior that also was highly offensive to the Lord; he was a lying, deceitful, phony. He went in to Tamar like he was going to do his duty; to all those outside he appeared to do his duty, but he never intended to fulfill his obligation at all. It was all an act. His behavior was similar to that of Ananias and Sapphira many centuries later. They also had a secret scheme to appear like they were doing something more than they actually were, and they paid for it with their lives (Act 5).
After Onan's death Judah told Tamar, "Remain a widow at thy father's house, till Shelah my son be grown: for he said, Lest peradventure he die also, as his brethren did" (Gen 38:11) He still claims he wants to try and do right with Tamar, but his third son was too young to marry, so she needs to wait on him. Judah is also "gun-shy" about giving Shelah to her at all. He already lost two sons to her and may fear she is some type of "black widow" who somehow kills her husbands. Notice Judah's words in vs 11 where he says, "...for he said, Lest peradventure he die also, as his brethren did...." In the first part of the verse he is speaking to Tamar, but with the last words he appears to be speaking to himself. This indicates Judah understood that at least Onan's death (and maybe Er's as well) was "seed" related. If Shelah had only recently entered into puberty, Judah may have feared that if he gave Tamar to him at such a tender yet hormone ravaged age, he may have prematurely spilled his seed before he could actually marry her. Judah was afraid to risk his only remaining son.
Readers of the Scriptures know what happens next. Shelah grows up but Judah doesn't give him to Tamar. In the meanwhile Judah's wife dies and Tamar sees an opportunity. Apparently, she believed Judah had an eye for "the ladies" and she dresses up as a harlot, Judah takes the bait, and she conceives twins. One of them, Pharez, is an ancestor of Jesus Christ.
These "seed" matters concerning Judah, Er, Onan, and Tamar show how significant and important they were to the early Hebrews. They were very concerned with protecting their family line and a deceased son being able to continue his name by proxy through a brother. The male seed propagation idea detailed in chapters one and two fits in the passage very well. They understood that the male must pass his seed to the woman for her to get pregnant, but they were unaware the woman also has a "seed" (egg) that must fuse with the male seed for a new life to form.
Another observation is the act of marriage is clearly defined as going "in unto" a woman and becoming "one flesh" with her in sexual union. However, a couple is only considered "husband and wife" if they are contracted or agree to live as such. Notice, Onan was to take Tamar as his "wife" as Shelah was in Gen 38:14, but even though Judah went in unto Tamar and in that sense married her, he is never called her husband nor she his wife. The difference boils down to intent. He had no intention of being husband to a harlot. The marriage was essentially dissolved when they separated.