Your name should no longer be called Abram, but your name shall be Abraham; for I have made you the father of a multitude of nations. (Bereishis 17:5)
The gemora tells us that a person who calls Avraham by the name “Avram” after the name change has transgressed a commandment of the Torah. Yet we find that after Hashem called “Yaakov” by the name “Yisrael”, Hashem Himself still called him “Yaakov” and we refer to him as the patriarch “Yaakov”. We use the name “Yisrael” when speaking about the congregation of the Jewish people or something specific which Yaakov Avinu did, but his original name still remains.
Aside from the halachic question as to why it is permissible to call Yaakov by the name “Yaakov”, there must be some reason behind the disparity as to how we relate to these name changes. The mashgiach of Torah Ohr, Rav Zeidel Epstein zt”l offers the following explanation: When Avraham had his name changed, Chazal tell us that it was attributed to the fact that Avraham gained control of five additional parts of his body, meaning full control of all 248 parts. Calling him “Avram” after this point would be insinuating that Avraham didn’t have control over these five body parts—hinted to by the missing letter “hey”. Not only would this be disrespectful, but it would be incorrect. Therefore, he may not be called “Avram”.
However, “Yaakov” was called “Yisrael” due to his ability to overpower even an angel. This new name was not an appreciation of his wholesomeness, but instead refers to a certain attribute that he had. On the other hand, the name “Yaakov” symbolizes another attribute that he had, as Esav tells us “that he held him back (outwitted me) twice”. Yaakov has the ability to maneuver himself even in the most complicated situations. This trait was not lost or forgotten from the persona of who Yaakov was. Therefore he can be called by either name.
On pondering this idea, I would like to comment that many of us in our growth accomplish many different things. Sometimes these accomplishments actually overhaul who we are and sometimes they just add another dimension to who we are or how we see things. Our job is to determine when to completely let go of the past and move on to something new, and when instead to embrace the past together with new growth, and become a more well-rounded person with both dimensions together.
Rav Hutner was fond of saying about the Yiddish expression used after Yom Tov has passed “Vi Iz aribbe d’Yontif?” meaning “How did the Yom Tov pass?” “How did you make it through?” and he said that the correct expression should be “Vi iz tzugekumen d’Yontif?” – “What was added onto your life through the Yom Tov?”
Sufficient time has now passed since Yom Tov so that we can now ask ourselves “What did I gain from the month of festivities (Chodesh Eitanim)?” Hopefully we have all risen to the occasion to be “Bnei Yisrael.”