תני לא שיעקר שם יעקב אלא ישראל עיקר ויעקב טפל, ר' זכריה מש' ר' אחא מכל מקום יעקב שמך אלא ״כי אם ישראל יהיה שמך„ יעקב עיקר וישראל טפל מוסיף עליו.
It was taught: The purpose was not to uproot the name Jacob, rather that Israel should be the primary name, and Jacob the secondary. R’ Zechariah said in the name of R’ Ahah “In any case, Jacob is your name, ‘but Israel will be your name.’ Jacob is the primary name, and Israel is the secondary that is added to it.
Genesis Rabba records a debate about which of Jacob’s names was the main one. What does this debate even mean? After Gd changes his name, he appears to be called by either Jacob or Israel interchangeably. Clearly then, both names were supposed to be used. If so, then perhaps we can speak of a primary and secondary name, as we can speak of a primary and secondary food eaten together. Yet the names are never used in tandem. If he is called Israel, he is not call Jacob, and if he is called Jacob, he is never called Israel.
Furthermore, the names symbolize opposing concepts. We are told the word Jacob — יעקב comes from the word עקב — heel. The lowest and hindmost organ is symbolic of effacement and lowliness. Israel — ישראל — appears to be from the root SRH שׂרה, which only appears in the context of defining the word Israel, but apparently means to strive or exert. The word also appears to be related to a second root SRR, שׂרר, meaning to dominate or rule.
Each name also invokes a pun, and these, too, are opposite. Esau says “הֲכִי קָרָא שְׁמוֹ יַעֲקֹב, וַיַּעְקְבֵנִי זֶה פַעֲמַיִם”, “It is fitting that he is called Jacob, for he tricked me twice.” Here the root עקב is used to mean crooked and underhanded. Meanwhile Moses called Israel ישׁרון with a shin, a name that equates Israel with ישׁר meaning upright or straight. In every meaning or allusion, the two names could never be so far apart.
This explains why Jacob is never simultaneously referred to by both names. One cannot be both effacing and dominant, both underhanded and upright at the same time. But then in what sense could Jacob keep both names? Logically, one name should entirely supplant the other. But that is not Jacob, and nor is it the people who came from him. There are times when they are dominant and upright and times when they lowly and survive on trickery.
The argument in Genesis Rabba is that given that Jacob/Israel embodies the characteristics of of both names, which is the one it embodies more? The first opinion believes that we can look at results. Israel survived in Laban’s house and came out with a large family and wealth. He outlasted the angel. He reconciled with Esau and emerged unharmed from the tense encounter. He is Israel who outlasts all who oppose him and comes out on top. So too, at the end of days, will his nation once again be Israel.
But R’ Zechariah looks at the journey. Jacob is the name he has now. In every moment, life is an eternal series of struggles and challenges. Jacob himself would face further tragedies and escape by the skin of his teeth. His nation certain faces its share of hardships and often ends up on the bottom. Israel is only the secondary, the guarantee they will survive to strive and prevail.
Jacob himself uses the name Israel self-referentially only once. He builds an altar in Shechem, and he calls it with the name Israel. He is harshly criticized for this by the Midrash. To the Sages, it was as if he had said he is the undisputed ruler below, as Gd is above. Immediately afterward, his family is thrown into several more perils, and the statement of the Sages becomes clear. One is never only Israel until the end. Until then one has to cope with also being Jacob.