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.

Wherefore he slew him also - The sin of Onan has generally been supposed to be self-pollution; but this is certainly a mistake; his crime was his refusal to raise up seed to his brother, and rather than do it, by the act mentioned above, he rendered himself incapable of it. We find from this history that long be fore the Mosaic law it was an established custom, probably founded on a Divine precept, that if a man died childless his brother was to take his wife, and the children produced by this second marriage were considered as the children of the first husband, and in consequence inherited his possessions.

Then said Judah to Tamar his daughter in law,.... After the death of his two sons, who had successively married her:

remain a widow at thy father's house till Shelah my son be grown: who was his third and youngest son, though perhaps not more than a year younger than Onan; but he might not choose he should marry so soon as his brethren had done, for a reason following: according to the custom and law of marrying a brother's wife, who died without issue, she in course was to be the wife of Shelah; since if there were ever so many brothers, they all married such an one in turn, until there was issue by one of them, see Mat 22:25; as Judah knew this, he pretended at least to give her to his son for wife, only would have it put off till he was at age of maturity, or was more grown; and therefore desires her to keep herself unmarried to any other person until that time; and advises her to go to her father's house, and continue there, which he did to prevent any intrigues between them, lest his son should be tempted to marry her sooner than it was his will, and she should solicit him to it:

for he said; not to Tamar, but within himself:

lest peradventure he die also as his brethren did; by which it seems, that he was ignorant of the true cause of their death, but thought it was either owing to their marrying too young, or to something in the woman unfortunate and unhappy; and he might not really intend he should marry her at all, only made use of an excuse for the present:

and Tamar went and dwelt in her father's house; she had dwelt in Judah's house in the time of her two husbands, but now by his advice she removed to her own father's house; which very probably was in the same place, and her father yet living, who received her, and with whom she continued, see Lev 22:13.

Judah said unto Onan . . . marry her, and raise up seed to thy brother--The first instance of a custom, which was afterwards incorporated among the laws of Moses, that when a husband died leaving a widow, his brother next of age was to marry her, and the issue, if any, was to be served heir to the deceased (compare Deu 25:5).