Moed Katan 8b
מועד קטן ח׳ ב — ד"ה מַתְנִי׳ אֵין נוֹשְׂאִין נָשִׁים בַּמּוֹעֵד
Moed Katan 8b:7
The mishna prohibits marriage during the intermediate days of a Festival because it constitutes a joyous occasion, and the Gemara explains that one may not mix two joys together, as each requires its own separate celebration, or alternatively, because marriage would cause one to abandon the Festival's rejoicing for his wife's sake.
מַתְנִי׳ אֵין נוֹשְׂאִין נָשִׁים בַּמּוֹעֵד, לֹא בְּתוּלוֹת וְלֹא אַלְמָנוֹת, וְלֹא מְיַיבְּמִין — מִפְּנֵי שֶׁשִּׂמְחָה הִיא לוֹ. אֲבָל מַחְזִיר הוּא אֶת גְּרוּשָׁתוֹ. גְּמָ׳ וְכִי שִׂמְחָה הִיא לוֹ, מַאי הָוֵי? אָמַר רַב יְהוּדָה אָמַר שְׁמוּאֵל, וְכֵן אָמַר רַבִּי אֶלְעָזָר אָמַר רַבִּי אוֹשַׁעְיָא, וְאָמְרִי לַהּ: אָמַר רַבִּי אֶלְעָזָר אָמַר רַבִּי חֲנִינָא: לְפִי שֶׁאֵין מְעָרְבִין שִׂמְחָה בְּשִׂמְחָה. רַבָּה בַּר [רַב] הוּנָא אָמַר: מִפְּנֵי שֶׁמַּנִּיחַ שִׂמְחַת הָרֶגֶל וְעוֹסֵק בְּשִׂמְחַת אִשְׁתּוֹ.
MISHNA: One may not marry a woman on the intermediate days of a Festival, not virgins and not widows, and one may not perform levirate marriage with his sister-in-law, if his brother died childless, because it is a joyous occasion for him. However, one may remarry his divorced wife on the intermediate days of a Festival, as this is not as great a joy for him. GEMARA: It was taught in the mishna that one may not marry a woman on the intermediate days of a Festival, because it is a source of joy for him. The Gemara asks: And if it is a source of joy for him, what of it? Isn’t there is a mitzva to rejoice on a Festival? Rav Yehuda said that Shmuel said, and, so too, Rabbi Elazar said that Rabbi Oshaya said, and some say that Rabbi Elazar said that Rabbi Ḥanina said: The reason that one may not get married on the intermediate days of a Festival is because one may not mix one joy with another joy, as each requires its own celebration. Rabba bar Rav Huna said: The reason is because he forsakes the rejoicing of the pilgrimage Festival and occupies himself with rejoicing with his wife.