1 ¶ And it came to pass at that time, that Judah went down from his brethren, and turned in to a certain Adullamite, whose name was Hirah. 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. 11 Then said Judah to Tamar his daughter in law, 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. And Tamar went and dwelt in her father’s house.
If you recall, the excuse that Rebekah used for sending Jacob away was the concern about the daughters of Heth, Canaanite women, from whom Esau selected his wives. Here, Judah, who we now know as being in Christ’s genealogy rather than his elder brother Reuben, has relations with a Canaanite woman, the daughter of Shuah. She bore him three sons; Er, Onan, and Shelah. Judah arranged a wife for Er, named Tamar, but God killed Er who was wicked.
Judah’s command to Onan to father children by his dead brother’s wife comes to us in a modern word for the system called a Levirate. In a society where women have no political and little economic power this system can provide a protector and offspring, a male child being the only support in old age for a widow. More importantly to Judah and Onan in this culture the system provides for a man’s physical lineage to continue by his brother being a proxy. Compare, if you will, the similar action of a woman providing her maid as a surrogate wife to bear children for her husband as we have already discussed. The Levirate has been practiced in several African cultures, as well.
Onan resented his duty to provide offspring in his brother’s place and practiced a form of birth control we call Coitus Interruptus but has been known, because of this Bible character, as Onanism, named after Onan, came to mean any sexual act that was not meant to produce offspring. This even was carried over into birth control as a sin still not long ago. Onan’s unwillingness to obey his father invoked God’s displeasure. Onan clearly knew that Er was the firstborn and any child considered his would be the heir of Er and his father, Judah’s, wealth, in the main. We see later in the Law given to Moses how standards of long practice are confirmed by God. In this case the Levirate will be called for in the Law given to Moses.
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. 7 And if the man like not to take his brother’s wife, then let his brother’s wife go up to the gate unto the elders, and say, My husband’s brother refuseth to raise up unto his brother a name in Israel, he will not perform the duty of my husband’s brother. 8 Then the elders of his city shall call him, and speak unto him: and if he stand to it, and say, I like not to take her; 9 Then shall his brother’s wife come unto him in the presence of the elders, and loose his shoe from off his foot, and spit in his face, and shall answer and say, So shall it be done unto that man that will not build up his brother’s house. 10 And his name shall be called in Israel, The house of him that hath his shoe loosed.
This is evident in the book of Job, for instance, in seeing that people knew God’s standard long before the Law was given. Many of the Laws God gave to Moses were not new things but the reinforcement of old standards along with new commands separating the Hebrews from the behavior of the Canaanites.
Christ, the Redeemer of mankind, will come through Judah so there is some importance here that goes beyond simply rebelling against your father’s wishes so that you inherit all rather than your dead brother’s heir that you helped make.
God kills Onan. Who knows how? A heart attack, an aneurysm, or some other of the million or so ways that God uses to end our physical lives, takes him. Judah tells his unfortunate and perhaps traumatized daughter-in-law, Tamar, to live in his house until his youngest and only remaining son, Shelah, is old enough to secure an offspring. Now, the story gets even stranger, if that were possible. This story was certainly not invented by someone trying to glorify an ancestor or justify a leader’s position of authority. It is remarkably disgusting as some Bible stories tend to be. It certainly isn’t how you or I would write Christ’s lineage unless we were simply reporting the unpleasant and unvarnished truth.
One thing that this story represents is how God makes a plan out of the wreck and unseemly life you create for yourself. For all of your wickedness you cannot thwart God’s will.