The gemara says in Taanis (5b):
...א"ר יוחנן יעקב אבינו לא מת א"ל וכי בכדי ספדו ספדנייא וחנטו חנטייא וקברו קברייא א"ל מקרא אני דורש שנאמר (ירמיהו ל, י) ואתה אל תירא עבדי יעקב נאם ה' ואל תחת ישראל כי הנני מושיעך מרחוק ואת זרעך מארץ שבים מקיש הוא לזרעו מה זרעו בחיים אף הוא בחיים
“Rabbi Yochanan said Yaakov Avinu did not die. He said to him, was it for nothing that they were maspid him and embalmed him? He said, I am making a derosho from a passuk as it says – ‘And you do not fear my servant Yaakov says Hashem and do not tremble Yisroel because I will save you from afar and you children from the land of their captivity.’ – The possuk compares Yaakov to his children, just as his children are alive so is he alive.”
How did Rebbi Yochanan answer the question. The possuk says in Vayechi that they embalmed Yaakov and were maspid him, so this contradicts the derosho from Yirmiya?
Rabbi Yitzchok Hutner zt”l explains that derush is not only a different way of making a limud than peshat. Just as derush is not discernible from a simple reading of the passuk, so too when the passuk relates events that occurred through derush, the events themselves were not necessarily visibly discernible. To the casual observer, Yaakov died and was embalmed. In a way that is not discernible to the untrained eye, Yaakov Avinu did not die. יעקב אבינו לא מת occurred in the world of derush, however the fact that Eliyohu was oleh lerakiya is explict in the passuk and was visible to the human eye. Eliyohu achieved chayey olam in olam hazeh, which is why he is the one chosed to announce the same level for everyone before mashiach comes.
The benei yisroel achieved this madregah at two different times.
The possuk says “vehachut hameshulosh lo bimherah yinatek”, the gemara explains - “the three ply rope, of Avrohom, Yitzchok and Yaakov, will not soon be snapped”. Yaakov only made the final step to completing the three ply rope after he beat the sar shel esav. After this he became Yisroel and the father of the benei yisroel, not just the shevatim. We know that ‘ein misoh la’tzibbur’ – a tzibbur never dies. Hashem promised klal yisroel that they would always be sustained. Hence, after the struggle with the sar shel Esav, Yaakov achieved chayey netzach for the benei yisroel as a whole.
Achieving chayey netzach for the individual was begun by Yaakov when he was niftar and completed by Eliyohu when he was oloh ba’searah hashamaymah.
The sar shel esav is the satan, and the gemara says (Bava Basra 16a):
אמר ר"ל הוא שטן הוא יצר הרע הוא מלאך המות
“Resh Lokish said, the satan is the yetzer hara and is also the malach hamaves.”
By defeating the yetzer hara, Yaakov also defeated the malach hamaves, initially for klal yisroel as a whole, later for Yaakov and Eliyohu hanavi personally and ultimately for the whole of klal yisroel.