1. The great שכר for the easy mitzvah of שילוח הקן

The next Mishnah states that one may not take a mother bird while it is on its young, even to purify a metzora (as explained on the previous Daf). It concludes: ומה אם מצוה קלה שהיא כאיסר – Now, if even for an easy mitzvah, which involves the loss of only an איסר, the Torah said you should perform it "למען ייטב לך והארכת ימים" – so that it will be good for you and you will live long, קל וחומר על מצות חמורות שבתורה – then how much more so does this apply to the difficult mitzvos in the Torah!

1. Rebbe Yaakov: שכר written in the Torah refers to עולם הבא (כיבוד אב ושילוח הקן incident with son)

In a Baraisa, Rebbe Yaakov says that there is not a single mitzvah in the Torah, whose reward is written together with it, that תחיית המתים is not dependent on it (i.e., תחיית המים is necessary for receiving their reward). He explains: the Torah promises long life for honoring one’s parents, as well as for performing שילוח הקן. But what of a son who climbs a tower and sends away a mother bird to obtain the young birds to fulfill his father’s request, and then falls and dies during his descent? היכן טובת ימיו של זה – Where is this person’s good life, והיכן אריכות ימיו של זה – and where is this person’s long life? Rather, we must say that למען יאריכון ימיך – so that your days be prolonged refers to life בעולם שכולו ארוך – in a world which is entirely long, and ולמען ייטב לך – so that it will be good for you refers to life לעולם שכולו טוב – in a world which is entirely good, i.e., עולם הבא. The Gemara adds that Rebbe Yaakov himself saw such an incident.

Rav Yosef commented that if Acher had interpreted this passuk like his grandson Rebbe Yaakov did, he would not have sinned. According to one version, Acher witnessed a similar incident.

1. שלוחי מצוה אינן נזוקים, but this does not apply in a מקום דקבוע היזקא

The Gemara questions Rebbe Yaakov’s proof that the Torah’s reward cannot refer to this world from the incident of a son dying while performing the mitzvos of כיבוד אב and שילוח הקן: perhaps he was thinking about committing a sin!? [Although Hashem does not punish for most sinful thoughts, but He does for idolatrous thoughts.] The Gemara answers that Rebbe Yaakov argued that if there is a reward in this world for mitzvos, the mitzvah should have protected him from having the sinful thoughts and coming to harm. The Gemara objects that Rebbe Elazar said שלוחי מצוה אינן נזוקים – those sent to perform a mitzvah are not harmed, לא בהליכתן ולא בחזרתן – neither on their way to do the mitzvah, nor on their return!? It answers: סולם רעוע הוה – it was a weak ladder which the son climbed, ומקום דקבוע היזקא שאני – and a place where the danger for harm is clearly established is different, and the protection for שלוחי מצוה is not guaranteed there. We find that Shmuel HaNavi expressed concern that Shaul would kill him for anointing Dovid as king, although Hashem had instructed him to do so.