Yaakov Avinu didn't die and connection to not eating?

Question

In Taanis 5b there is a story with two amoraim

רב נחמן ור' יצחק הוו יתבי בסעודתא א"ל רב נחמן לר' יצחק לימא מר מילתא א"ל הכי א"ר יוחנן אין מסיחין בסעודה שמא יקדים קנה לושט ויבא לידי סכנה

Where its says that one shouldn't talk whilst eating since it is dangerous.

The Gemara then continues:

בתר דסעוד א"ל הכי 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

Why is this the first thing for Rav Yitzchak to say after eating that Yaakov Avinu didn't die?

Answer 1

In a lengthy comment on this Talmudic passage in Ben Yehoyada, R. Joseph Hayyim of Baghdad addresses this question.

He begins with a different question: how is it possible that R. Nachman was unaware of the law that one must not talk while eating? Furthermore, how could R. Yitzchak respond? The very statement he was quoting forbids making the statement! Additionally, many great rabbis throughout the generations have not followed this law, and in fact do talk while eating.

He provides two possible reasons why it would not have been problematic in this situation. The first is that this law only applied when people while leaning. In such a situation it was indeed dangerous to speak while eating, but when eating sitting upright there is no danger. R. Nachman felt justified in talking while they were eating because they weren't leaning. R. Yitzchak responded by quoting the statement of R. Yochanan. R. Yochanan's statement was short and to the point – you can't talk while eating. He didn't say that it only applies in certain situations. While a tanna can issue a vague pronouncement without delineating the parameters, an amora is obligated to explain his statements. Thus, the fact that R. Yochanan did not specify that this law is only aplicable when leaning means that it is in fact applicable even when not leaning. The reason for this is that even though it is not dangerous in such a situation, we forbid it on account of the situations where it is dangerous. R. Yitzchak felt that teaching this to R. Nachman was sufficient reason to override the secondary decree.

The alternative explanation is that while it is dangerous to talk while eating, it is irrelevant when the speech is words of Torah since the mitzvah (of Torah study) would protect them from harm. R. Nachman therefore felt justified in engaging in a Torah conversation. R. Yitzchak however felt that even though speaking words of Torah is not dangerous it still must not be done because onlookers may not realize that it is words of Torah being spoken, and they may then think that it is okay to talk about anything while eating.

This is where we get to the relevance of the statement about Yaakov not dying. R. Yitzchak was making the argument that we have to be concerned about onlookers making a mistake. He thus cited the statement about Yaakov to buttress his argument. Since they embalmed, eulogized, and buried Yaakov even though he didn't die, we see that they were concerned about the onlookers mistakenly thinking that Yaakov was a god. If so, we too must be concerned about onlookers mistakenly thinking to is fine to talk about anything while eating, and therefore we must refrain even from talking about Torah which poses no danger.

Answer 2

Most likely due to the fact that first Rav Yitzchak quoted Rav Yochonan when he told told Rav Nachman that one should not talk when eating. Then when he finished eating, he continued to quote Rav Yochanan on another matter (Yaakov lo mes). This is not unusual in shas to string quotes of an amorah together. There are many examples in shas, here is one - Shavuous 47b Shimon be Tarfon.

Without having a source, I would say further that since Rav Yitzchak quoted Rav Yochanan first to reprimand Rav Nachman, he then brought another Rav Yochanan in a more positive way as opposed to quoting another thought from someone else.