אורח חיים תרצ״זOrach Chayim 697

Se’if 1א׳

יוֹם י"ד וְט"ו שֶׁבַּאֲדָר רִאשׁוֹן אֵין נוֹפְלִים עַל פְּנֵיהֶם, וְאֵין אוֹמְרִים מִזְמוֹר יַעַנְךָ ה' בְּיוֹם צָרָה, וַאֲסוּרִים בְּהֶסְפֵּד וְתַעֲנִית; אֲבָל שְׁאָר דְּבָרִים אֵין נוֹהֲגִים בָּהֶם; וְיֵשׁ אוֹמְרִים דְּאַף בְּהֶסְפֵּד וְתַעֲנִית מֻתָּרִים. הַגָּה: וְהַמִּנְהָג כַּסְּבָרָא הָרִאשׁוֹנָה. יֵשׁ אוֹמְרִים שֶׁחַיָּב לְהַרְבּוֹת בְּמִשְׁתֶּה וְשִׂמְחָה בְּ"ד שֶׁבַּאֲדָר רִאשׁוֹן (טוּר בְּשֵׁם הָרִי"ף) וְאֵין נוֹהֲגִין כֵּן, מִכָּל מָקוֹם יַרְבֶּה קְצָת בִּסְעֻדָּה כְּדֵי לָצֵאת יְדֵי הַמַּחְמִירִים; (הַגָּהוֹת מַיְמוֹנִי בְּשֵׁם סְמַ"ק) וְטוֹב לֵב מִשְׁתֶּה תָּמִיד (מִשְׁלֵי ט"ו, ט"ו).

One does not say Tachanun on the 14th and 15th of Adar I, and the law of fasting and eulogizing on those days. Containing one paragraph. On the 14th and the 15th day of Adar I, we do not fall upon our faces [recite Tahanun], and we do not say [Psalm 20] "A Psalm... may the Lord answer you," and on those [days], it is forbidden to eulogize or to fast. There are those who say that even eulogy and fasting are permitted. Rema: The custom is according to the first understanding. There are those who say that one is obligated to increase in joy and feasting on the 14th of Adar I (Tur in the name of the Rif); however, this is not our practice. Nevertheless, one should increase their feasting slightly, in order to fulfill the opinion of those who are stringent (Hagahot Maimuni in the name of the SeMaK). "But the good-hearted has a continual feast" (Proverbs 15:15).