Comentario citado sobre Jeremías 9:3

ויאמר, when Esau heard that his brother had used subterfuge to obtain the blessing by making his hands appear as if they were hairy, he said: הכי קרא שמו יעקב, “he was called the crooked one for good reason!” The letter ה at the beginning of the word הכי serves as confirmation of something, as if to say: “truly!” We find it used in a similar sense in Kings I 21,19 הרצחת וגם ירשת!, “ You not only murdered but meant to inherit!” Or, Numbers 20,10: המן הסלע הזה! “from this very rock!” Esau said that Yaakov had truly deserved the name they had given him at birth. Actually, the word יעקב has two connotations; one is connected to deviousness, deceit, as in Jeremiah 17,10 עקוב הלב , “the heart is full of deceit;” or, also from Jeremiah 9,3 כי כל אח עקוב יעקב, “every brother takes advantage.” On the other hand, the word also is derived from עקב, heel, not a negative connotation at all, but possibly a positive one, suggesting humility, modesty, the opposite of pushiness. Yaakov combined both qualities.