cellio | daf bit: Sukkah 25

(Today's daf is 24 and concerns various materials that can form walls for a sukkah. But I read ahead a little and chose this instead.)

The mishna teaches: those who are engaged in a religious errand are exempt from the obligation of the sukkah. Invalids and their attendants are free from the obligation of sukkah. And casual eating and drinking (but not a set meal) are permitted outside the sukkah. The g'mara discusses the first case here and draws support from the Sh'ma: "when you sit in your house" excludes one who is occupied with a religious duty (and therefore not sitting in his house). However, the rabbis clarify that this applies only to one who is busy with a religious matter, and doesn't apply to someone who is out and about for secular reasons -- that man is still obligated in the sukkah. (There is an explanation, and if I read it a few more times perhaps I will understand it.) (25a)

It's not stated here, but I assume that the rabbis are connecting "when you sit in your house" with the commandment to sit in the sukkah, which acts as a temporary dwelling. I assume -- but the g'mara does not say -- that the exemption only applies for the amount of time it takes you to perform the religious errand. And I suspect the actual halacha is more complicated in any case.

There is a principle, I believe from the talmud, that you do not interrupt one mitzvah in order to do another. (And I suspect that is more complicated too; I would expect "need to do it right now" mitzvot and time-optional ones to be different, but I don't know.) The g'mara doesn't bring up that principle here, at least so far. That surprised me.