Komentarz do Rodzaju 38:7

רע בעיני ה' WAS WICKED IN THE EYES OF THE LORD — like the wickedness of Onan, and committing the same sin. This must have been the case because of Onan it is said, (v. 10) “And the Lord slew him also — Onan’s death was for a similar reason as Er’s death. Why did Er commit this sin? So that she should not bear children and her beauty thereby become impaired (Yevamot 34b).

AND ER, JUDAH’s FIRSTBORN, WAS WICKED IN THE SIGHT OF THE ETERNAL. Scripture does not specify the nature of his wickedness as it did in the case of his brother.¹⁴⁸Verse 9 here. Instead, it simply states that he died for his own sin. It informs us that this was not by way of punishment of Judah for his role in the sale of Joseph, since the saving of Joseph’s life by Judah compensated for his role in the sale. There was no case of death of a child in the house of the patriarchs except this one who was wicked in the sight of the Eternal, since the race of the righteous is blessed. This is why Jacob mourned many days for his son Joseph, and he refused to comfort himself,¹⁴⁹Above, 37:34-35. for he considered this to be a great punishment to himself, quite apart from his love for him.

ויהי ער רע בעיני ה', the words “in the eyes of G’d,” are mentioned to tell us that he was not evil to his fellow human beings.