The Chinukh treats sanctifying months and establishing the festivals as a mitzvah connected to the rhythms of sacred time. It broadens 'kedushat hazman' to the calendar itself.
מִצְוַת קִדּוּשׁ הַחֹדֶשׁ – לְקַדֵּשׁ חֳדָשִׁים וּלְעַבֵּר שָׁנִים בְּבֵית דִּין גָּדוֹל בְּחָכְמָה סָמוּךְ בָּאָרֶץ, וְלִקְבֹּעַ מוֹעֲדֵי הַשָּׁנָה עַל פִּי אוֹתוֹ קִדּוּשׁ, שֶׁנֶּאֱמַר (שמות יב ב) הַחֹדֶשׁ הַזֶּה לָכֶם רֹאשׁ חֳדָשִׁים, כְּלוֹמַר כְּשֶׁתִּרְאוּ חִדּוּשָׁהּ שֶׁל לְבָנָה, תִּקְבְּעוּ לָכֶם רֹאשׁ חֹדֶשׁ, אוֹ אֲפִלּוּ לֹא תִּרְאוּהָ, מִכֵּיוָן שֶׁהִיא רְאוּיָה לְהֵרָאוֹת עַל פִּי הַחֶשְׁבּוֹן הַמֻּקְבָּל. וְכֵן תִּכְלֹל מִצְוָה זוֹ מִצְוַת עִבּוּר הַשָּׁנָה, לְפִי שֶׁיְּסוֹד מִצְוַת קִדּוּשׁ הַחֹדֶשׁ, כְּדֵי שֶׁיַּעֲשׂוּ יִשְׂרָאֵל מוֹעֲדֵי הַשֵּׁם בְּמוֹעֲדָם. וּכְמוֹ כֵן מִצְוַת עִבּוּר הַשָּׁנָה מִזֶּה הַיְּסוֹד הִיא. וְאוּלָם מִלְּבַד זֶה הַמִּקְרָא בָּאוּ הֶעָרוֹת בִּכְתוּבֵי הַתּוֹרָה יוֹרוּ עַל מִצְוַת הָעִבּוּר, וְהוּא מָה שֶׁכָּתוּב (שם יג י) וְשָׁמַרְתָּ אֶת הַחֻקָּה הַזֹּאת לְמוֹעֲדָהּ. וְכֵן (דברים טז א) שָׁמוֹר אֶת חֹדֶשׁ הָאָבִיב. מִשָּׁרְשֵׁי מִצְוָה זוֹ, כְּדֵי שֶׁיַּעֲשׂוּ יִשְׂרָאֵל מוֹעֲדֵי הַשֵּׁם בִּזְמַנָּם, שֶׁהַשֵּׁם יִתְבָּרַךְ צִוָּה לַעֲשׂוֹת פֶּסַח בִּזְמַן שֶׁהַתְּבוּאָה בָּאָבִיב כְּמוֹ שֶׁכָּתוּב שָׁמוֹר אֶת חֹדֶשׁ הָאָבִיב וְעָשִׂיתָ פֶּסַח. וְחַג הַסֻּכּוֹת בִּזְמַן הָאָסִיף, כְּמוֹ שֶׁכָּתוּב (שמות לד כב) וְחַג הָאָסִיף תְּקוּפַת הַשָּׁנָה. וְאִלּוּלֵי עִבּוּר הַשָּׁנִים, יָבֹאוּ הַמּוֹעֲדִים שֶׁלֹּא בִּזְמַנִּים אֵלּוּ, לְפִי שֶׁיִּשְׂרָאֵל מְחַשְּׁבִים חָדְשֵׁיהֶם וּמוֹעֲדֵיהֶם לִימוֹת שְׁנַת הַלְּבָנָה, שֶׁהֵם שנ"ד יוֹם ח' שָׁעוֹת תתעו חֲלָקִים, וְהִיא חֲסֵרָה מִשְּׁנַת הַחַמָּה י' יָמִים, כ"א שָׁעוֹת, ר"ד חֲלָקִים, סִימָן י' כ"א ר"ד. וּבִשּׁוּל הַתְּבוּאוֹת וְהַפֵּרוֹת בְּכֹחָהּ שֶׁל חַמָּה, נִמְצָא שֶׁאִלּוּלֵי הָעִבּוּר, שֶׁאָנוּ מַשְׁוִים בּוֹ שְׁנוֹת הַלְּבָנָה בִּשְׁנוֹת הַחַמָּה, לֹא יָבֹא הַפֶּסַח בִּזְמַן הָאָבִיב וְהַסֻּכּוֹת בִּזְמַן הָאָסִיף. וְנִתְקַן הַדָּבָר לְהֵעָשׂוֹת בִּגְדוֹלֵי הַדּוֹר, לְפִי שֶׁהוּא עִנְיַן חָכְמָה גְּדוֹלָה, גַּם יֹאמְרוּ כִּי מִמֶּנּוּ יִוָּדַע מִקְרֵה הַשָּׁנָה בַּתְּבוּאוֹת, וְאֵין רָאוּי לְמָסְרוֹ אֶלָּא לִגְדֹלִים וַחֲסִידִים.
The commandment of sanctifying the new month: To sanctify months and intercalate [months into] years in the court [whose members are] great in wisdom and ordained in the Land of Israel, and to establish the year’s holidays according to that sanctification; as it is stated (Exodus 12:2), “This month shall be to you the first of months.” This means, when you see the renewal of the moon, establish for yourselves the new month — or even if you do not see it, since it is appropriate for [the moon] to appear according to the accepted calculation. Likewise, this commandment includes the commandment of intercalation, since the basis of the commandment to sanctify the month is for Israel to observe God’s holidays at their appointed times. And the commandment of intercalation has the same basis. However, beyond this verse are more Torah passages concerning the commandment of intercalation, and that is what is written (Exodus 13:10), “You shall observe this commandment in its proper time”; and likewise, “Observe the month of Spring” (Deuteronomy 16:1). It is from the roots of this commandment [that it is] so that Israel shall make God’s holidays in their (proper) times, as God commanded that we make Pesach in the time that the produce is in [bloom], as it is written (Deuteronomy 16:1), “Observe the month of Spring, and you shall offer the Pesach sacrifice.” And the holiday of Sukkot is [to fall] at the time of the harvest, as is written, “And the holiday of the harvest at the turn of the year” (Exodus 34:22). And were it not for intercalation, the holidays would come not at these times, since Israel calculates their months and festivals according to the lunar year, which has three hundred and fifty-four days, eight hours, and eight hundred and seventy-six parts, which is less than the solar year by ten days, twenty-one hours and two hundred and four parts — its mnemonic is ten, twenty-one, two hundred and four. Due to the ripening of the produce and fruit from the power of the sun, it turns out that but for intercalation — by which we align the lunar and solar years — Pesach would not come in the Spring, nor Sukkot at the time of the harvest. And this matter is to be fixed by the greatest [sages] of the generation, since it is a matter requiring great wisdom. And since it is also said that from this [calculation, one comes to know] the agricultural happenings of the year, it is appropriate to give [this task] only to great and pious men.