2. Question: Why does an onen who has involved himself in the burial of his relative have to repeat shema after he buries the dead even if he said it when he wasn’t supposed to while preparing to bury the dead but if one is in involved in any other mitzvah like a sofer who must be working when it’s time to say the Shema, if he does say it even though he is exempt from saying it while involved in another mitzvah he does not need to repeat Shema when he’s done with this mitzvah?
A. The Shulchan Aruch and Rema (Orach Chaim 38:8) say that those who write Tefillin and Mezuzos… and anyone who is involved in “the work of Heaven” are exempt from putting on tefillin the entire day besides by Shema and Shemone Esray. And if they need to do their job during the time, they should be saying Shema and Shemone esray then they are exempt from reciting Shema, Shemone esray and putting on tefillin because any one who is involved in one mitzvah is exempt from another if it would be hard to do the other one but if you can do both without any hassles then do both. The Be’ur halacha there adds in the name of the Ra”n that the Rambam says that even if you can do both you are exempt because when one is involved in doing Hashem’s work the Torah doesn’t bother you and obligate you to perform other mitzvos even if you can. However, the Shaar Hatzion later on (475:39) says that if you do the other mitzvah then you fulfill that mitzvah since he is a person who is obligated in the mitzvah it is just that the Torah doesn’t obligate you to perform it at this time and it’s unlike an insane person if he performs a mitzvah while legally insane, he does not get credit for performing it.
B. The Mishna Berura (71:3) says that an onen who recites the Shema or hears megillah (see Mishna Berura 696:26) must do it again after the burial. The reason given is out of respect for the dead, so that people won’t say that you don’t care about your dead relative, that he or she died.
Answer: Respect for you dead relative is different than respect for Hashem. Because if you do one of Hashem’s mitzvos while involved in another one you are still respecting Hashem because they are both His mitzvos therefore even though you shouldn’t do it if you do it, you don’t have to repeat it. But doing another mitzvah besides caring for the dead while you are supposed to be caring for the dead is a lack of honor to the dead so it’s as if the mitzvah was not fulfilled and therefore must be done again after the first mitzvah is finished. [/exempt]