Genesis 38:4

The story of Judah and Tamar is a carefully placed break in the larger story. It shows what was happening in Judah’s family. Judah would later become an important leader. The story also shows the early stages of the family mixing with the people of the land. This helps explain why God sent the family to Egypt (chapters 39–47).

The Egyptians kept themselves separate from other peoples (43:32). Because of that, the Israelites were more likely to keep their own identity in Egypt than in Canaan.

And Judah saw there a daughter of a certain Canaanite--Like Esau [Gen 26:34], this son of Jacob, casting off the restraints of religion, married into a Canaanite family; and it is not surprising that the family which sprang from such an unsuitable connection should be infamous for bold and unblushing wickedness.

Here is, 1. Judah's foolish friendship with a Canaanite-man. He went down from his brethren, and withdrew for a time from their society and his father's family, and got to be intimately acquainted with one Hirah, an Adullamite, Gen 38:1. It is computed that he was now not much above fifteen or sixteen years of age, an easy prey to the tempter. Note, When young people that have been well educated begin to change their company, they will soon change their manners, and lose their good education. Those that go down from their brethren, that despise and forsake the society of the seed of Israel, and pick up Canaanites for their companions, are going down the hill apace. It is of great consequence to young people to choose proper associates; for these they will imitate, study to recommend themselves to, and, by their opinion of them, value themselves: an error in this choice is often fatal. 2. His foolish marriage with a Canaanite-woman, a match made, not by his father, who, it should seem, was not consulted, but by his new friend Hirah, Gen 38:2. Many have been drawn into marriages scandalous and pernicious to themselves and their families by keeping bad company, and growing familiar with bad people: one wicked league entangles men in another. Let young people be admonished by this to take their good parents for their best friends, and to be advised by them, and not by flatterers, who wheedle them, to make a prey of them. 3. His children by this Canaanite, and his disposal of them. Three sons he had by her, Er, Onan, and Shelah. It is probable that she embraced the worship of the God of Israel, at least in profession, but, for aught that appears, there was little of the fear of God in the family. Judah married too young, and very rashly; he also married his sons too young, when they had neither wit nor grace to govern themselves, and the consequences were very bad. (1.) His first-born, Er, was notoriously wicked; he was so in the sight of the Lord, that is, in defiance of God and his law; or, if perhaps he was not wicked in the sight of God, to whom all men's wickedness is open; and what came of it? Why, God cut him off presently (Gen 38:7): The Lord slew him. Note, Sometimes God makes quick work with sinners, and takes them away in his wrath, when they are but just setting out in a wicked course of life. (2.) The next son, Onan, was, according to the ancient usage, married to the widow, to preserve the name of his deceased brother that died childless. Though God had taken away his life for his wickedness, yet they were solicitous to preserve his memory; and their disappointment therein, through Onan's sin, was a further punishment of his wickedness. The custom of marrying the brother's widow was afterwards made one of the laws of Moses, Deu 25:5. Onan, though he consented to marry the widow, yet, to the great abuse of his own body, of the wife that he had married, and of the memory of his brother that was gone, he refused to raise up seed unto his brother, as he was in duty bound. This was so much the worse because the Messiah was to descend from Judah, and, had he not been guilty of this wickedness, he might have had the honour of being one of his ancestors. Note, Those sins that dishonour the body and defile it are very displeasing to God and evidences of vile affections. (3.) Shelah, the third son, was reserved for the widow (Gen 38:11), yet with a design that he should not marry so young as his brothers had done, lest he die also. Some think that Judah never intended to marry Shelah to Tamar, but unjustly suspected her to have been the death of her two former husbands (whereas it was their own wickedness that slew them), and then sent her to her father's house, with a charge to remain a widow. If so, it was an inexcusable piece of prevarication that he was guilty of. However, Tamar acquiesced for the present, and waited the issue.

And Judah saw there a daughter of a certain Canaanite. I am not satisfied with the interpretation which some give of "merchant" to the word Canaanite. For Moses charges Judah with perverse lust, because he took a wife out of that nation with which the children of Abraham were divinely commanded to be at perpetual strife. For neither he nor his other brethren were ignorant that they sojourned in the land of Canaan, under the stipulation, that afterwards their enemies were to be cut off and destroyed, in order that they might possess the promised dominion over it. Moses, therefore, justly regards it as a fault, that Judah should entangle himself in a forbidden alliance; and the Lord, at length, cursed the offspring thus accruing to Judah, that the prince and head of the tribe of Judah might not be born, nor Christ himself descend, from this connection. This also ought to be numbered among the exercises of Jacob's patience, that a wicked grandson was born to him through Judah, of whose sin he was not ignorant. Moses says, that the youth was cut off by the vengeance of God. The same thing is not said of others whom a sudden death has swept away in the flower of their age. I doubt not, therefore, that the wickedness, of which death was the immediate punishment, was extraordinary, and known to all men. And although this trial was in itself severe to the holy patriarch; yet nothing tormented his mind more than the thought, that he could scarcely hope for the promise of God to be so ratified that the inheritance of grace should remain in the possession of wicked and abandoned men. It is true that a large family of children is regarded as a source of human happiness. But this was the peculiar condition of the holy patriarch, that, though God had promised him an elect and blessed seed, he now sees an accursed progeny increase and shoot forth together with his offspring, which might destroy the expected grace. It is said, that Er was wicked in the sight of the Lord, (Genesis 38:7.) Notwithstanding, his iniquity was not hidden from men. Moses, however, means that he was not merely infected with common vices, but rather was so addicted to crimes, that he was intolerable in the sight of God.

And it came to pass at that time - The facts mentioned here could not have happened at the times mentioned in the preceding chapter, as those times are all unquestionably too recent, for the very earliest of the transactions here recorded must have occurred long before the selling of Joseph. Mr. Ainsworth remarks "that Judah and his sons must have married when very young, else the chronology will not agree. For Joseph was born six years before Jacob left Laban and came into Canaan; Gen 30:25, and Gen 31:41. Joseph was seventeen years old when he was sold into Egypt, Gen 37:2, Gen 37:25; he was thirty years old when he interpreted Pharaoh's dream, Gen 41:46. And nine years after, when there had been seven years of plenty and two years of famine, did Jacob with his family go down into Egypt, Gen 41:53, Gen 41:54, and Gen 45:6, Gen 45:11. And at their going down thither, Pharez, the son of Judah, whose birth is set down at the end of this chapter, had two sons, Hezron and Hamul, Gen 46:8, Gen 46:12. Seeing then from the selling of Joseph unto Israel's going down into Egypt there cannot be above twenty-three years, how is it possible that Judah should take a wife, and have by her three sons successively, and Shelah the youngest of the three be marriageable when Judah begat Pharez of Tamar, Gen 38:14, Gen 38:24, and Pharez be grown up, married, and have two sons, all within so short a space? The time therefore here spoken of seems to have been soon after Jacob's coming to Shechem, Gen 33:18, before the history of Dinah, Genesis 34, though Moses for special cause relates it in this place." I should rather suppose that this chapter originally stood after Genesis 33, and that it got by accident into this place. Dr. Hales, observing that some of Jacob's son must have married remarkably young, says that "Judah was about forty-seven years old when Jacob's family settled in Egypt. He could not therefore have been above fifteen at the birth of his eldest son Er; nor Er more than fifteen at his marriage with Tamar; nor could it have been more than two years after Er's death till the birth of Judah's twin sons by his daughter-in-law Tamar; nor could Pharez, one of them, be more than fifteen at the birth of his twin sons Herron and Hamul, supposing they were twins, just born before the departure from Canaan. For the aggregate of these numbers, 15, 15, 2, 15, or 47 years, gives the age of Judah; compare Genesis 38 with Gen 46:12." See the remarks of Dr. Kennicott, at Gen 31:55 (note). Adullamite - An inhabitant of Adullam, a city of Canaan, afterwards given for a possession to the sons of Judah, Jos 15:1, Jos 15:35. It appears as if this Adullamite had kept a kind of lodging house, for Shuah the Canaanite and his family lodged with him; and there Judah lodged also. As the woman was a Canaanitess, Judah had the example of his fathers to prove at least the impropriety of such a connection.

And she conceived again, and bare a son,.... As soon as she well could:

and she called his name Onan; the first son Judah gave the name to, but his wife named this, so called from grief or sorrow; the reason of it, according to the above Targum, was,"because his father would mourn for him;''he was a Benoni, see Genesis 35:18, whose sin and immature death caused sorrow.

About this time, i.e., after the sale of Joseph, while still feeding the flocks of Jacob along with his brethren (Gen 37:26),
(Note: As the expression "at that time" does not compel us to place Judah's marriage after the sale of Joseph, many have followed Augustine (qusaet. 123), and placed it some years earlier. But this assumption is rendered extremely improbable, if not impossible, by the fact that Judah was not merely accidentally present when Joseph was sold, but was evidently living with his brethren, and had not yet set up an establishment of his own; whereas he had settled at Adullam previous to his marriage, and seems to have lived there up to the time of the birth of the twins by Thamar. Moreover, the 23 years which intervened between the taking of Joseph into Egypt and the migration of Jacob thither, furnish space enough for all the events recorded in this chapter. If we suppose that Judah, who was 20 years old when Joseph was sold, went to Adullam soon afterwards and married there, is three sons might have been born four or five years after Joseph's captivity. And if his eldest son was born about a year and a half after the sale of Joseph, and he married him to Thamar when he was 15 years old, and gave her to his second son a year after that, Onan's death would occur at least five years before Jacob's removal to Egypt; time enough, therefore, both for the generation and birth of the twin-sons of Judah by Thamar, and for Judah's two journeys into Egypt with his brethren to buy corn. (See Gen 46:8.))
Judah separated from them, and went down (from Hebron, Gen 37:14, or the mountains) to Adullam, in the lowland (Jos 15:35), into the neighbourhood of a man named Hirah. "He pitched (his tent, Gen 26:25) up to a man of Adullam," i.e., in his neighbourhood, so as to enter into friendly intercourse with him.
Gen 38:2-5
There Judah married the daughter of Shuah, a Canaanite, and had three sons by her: Ger (ער), Onan, and Shelah. The name of the place is mentioned when the last is born, viz., Chezib or Achzib (Jos 15:44; Mic 1:14), in the southern portion of the lowland of Judah, that the descendants of Shelah might know the birth-place of their ancestor. This was unnecessary in the case of the others, who died childless.
Gen 38:6-10
When Ger was grown up, according to ancient custom (cf. Gen 21:21; Gen 34:4) his father gave him a wife, named Thamar, probably a Canaanite, of unknown parentage. But Ger was soon put to death by Jehovah on account of his wickedness. Judah then wished Onan, as the brother-in-law, to marry the childless widow of his deceased brother, and raise up seed, i.e., a family, for him. But as he knew that the first-born son would not be the founder of his own family, but would perpetuate the family of the deceased and receive his inheritance, he prevented conception when consummating the marriage by spilling the semen. ארצה שׁחת, "destroyed to the ground (i.e., let it fall upon the ground), so as not to give seed to his brother" (נתן for תּת only here and Num 20:21). This act not only betrayed a want of affection to his brother, combined with a despicable covetousness for his possession and inheritance, but was also a sin against the divine institution of marriage and its object, and was therefore punished by Jehovah with sudden death. The custom of levirate marriage, which is first mentioned here, and is found in different forms among Indians, Persians, and other nations of Asia and Africa, was not founded upon a divine command, but upon an ancient tradition, originating probably in Chaldea. It was not abolished, however, by the Mosaic law (Deu 25:5.), but only so far restricted as not to allow it to interfere with the sanctity of marriage; and with this limitation it was enjoined as a duty of affection to build up the brother's house, and to preserve his family and name (see my Bibl. Archologie, 108).
Gen 38:11
The sudden death of his two sons so soon after their marriage with Thamar made Judah hesitate to give her the third as a husband also, thinking, very likely, according to a superstition which we find in Tobit 3:7ff., that either she herself, or marriage with her, had been the cause of her husbands' deaths. He therefore sent her away to her father's house, with the promise that he would give her his youngest son as soon as he had grown up; though he never intended it seriously, "for he thought lest (פּן אמר, i.e., he was afraid that) he also might die like his brethren."