Genesis 38:2

2. 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.