Kiddushin 35 - 41
Do It Yourself
"A man makes kiddushin by himself or through an agent."
This opening line of the second perek of our mesechta is challenged by the gemara as being redundant. If a man can effectively marry a woman through his agent's giving her money or a document, isn't it obvious that he can do so by himself?
Rabbi Yosef's explanation is that the mishna wishes to teach us that it is a greater mitzvah for a man to make kiddushin himself rather than to do it through an agent. As proof of this principle the gemara cites the examples of Rabbi Safra and the Sage Rava who personally helped prepare the food for Shabbat meals even though they could have delegated such work to their servants.
The examples cited find expression in the halacha (Shulchan Aruch Orach Chaim 250:1) which states that even if one has many servants to call upon, he should do something himself in preparation for Shabbat in order to honor it in the manner of the aforementioned sages.
A question is raised, however, by Mishna Berura (ibid. Shaar Hatziun 9) in regard to the behavior of those sages. The ruling of the gemara (Mesechta Mo'ed Katan 9b) is that one must interrupt his study of Torah in order to perform a mitzvah which cannot be done by another; but, if he is not indispensable for the fulfillment of the mitzvah, then he must continue his study. If these sages were able to have their servants make the Shabbat preparations for them, why did they see fit to interrupt their precious Torah study to do them?
One resolution of this problem is that the aforementioned rule of when one may or may not interrupt Torah study does not apply to mitzvot which are incumbent on the individual, only to acts of kindness which must be done for the sake of another Jew. Since that act can be performed by someone else not involved in Torah study there is no justification for interrupting Torah study. Honoring the Shabbat by preparing food for its meals, however, is a mitzvah which every Jew must do and it is therefore preferable to do it yourself than through an agent.