After they had eaten, he said to him: Thus said Rabbi Yochanan: Jacob our father did not die. He said to him: Was it for nothing that the eulogizers eulogized, and the embalmers embalmed, and the buriers buried? He said to him: I am interpreting a verse, as it is said: "And you, fear not, My servant Jacob, says the LORD, and be not dismayed, O Israel, for behold, I will save you from afar, and your seed from the land of their captivity" (Jeremiah 30:10). He likens him to his seed: just as his seed are alive, so too he is alive.
Jacob Never Died
Taanit 5b
בָּתַר דִּסְעוּד אֲמַר לֵיהּ, הָכִי אָמַר רַבִּי יוֹחָנָן: יַעֲקֹב אָבִינוּ לֹא מֵת. אֲמַר לֵיהּ: וְכִי בִּכְדִי סְפַדוּ סַפְדָּנַיָּא וַחֲנַטוּ חָנְטַיָּיא וּקְבַרוּ קַבָּרַיָּיא? אֲמַר לֵיהּ: מִקְרָא אֲנִי דּוֹרֵשׁ, שֶׁנֶּאֱמַר: ״וְאַתָּה אַל תִּירָא עַבְדִּי יַעֲקֹב נְאֻם ה׳ וְאַל תֵּחַת יִשְׂרָאֵל כִּי הִנְנִי מוֹשִׁיעֲךָ מֵרָחוֹק וְאֶת זַרְעֲךָ מֵאֶרֶץ שִׁבְיָם״, מַקִּישׁ הוּא לְזַרְעוֹ: מָה זַרְעוֹ בַּחַיִּים — אַף הוּא בַּחַיִּים.