צָרִיךְ הָאָדָם שֶׁיְּכַוַּן כָּל מַעֲשָׂיו, כֻּלָּם, כְּדֵי לֵידַע אֶת הַשֵּׁם בָּרוּךְ הוּא, בִּלְבָד; וְיִהְיֶה שִׁבְתּוֹ וְקוּמוֹ וְדִבּוּרוֹ, הַכֹּל לְעֻמַּת זֶה הַדָּבָר
A person should direct his heart and the totality of his behavior to one goal: becoming aware of God. The way one rests, rises, and speaks should all be directed to this end.That is, even the mundanities of life can raise us up, if we re-orient our thinking. Maimonides gets even more specific, citing work, diet, sex, and even sleep as being part of the pursuit of holiness:
וְאַפִלּוּ בְּשָׁעָה שְׁהוּא יָשֵׁן, אִם יָשֵׁן לַדַּעַת כְּדֵי שֶׁתָּנוּחַ דַּעְתּוֹ עָלָיו, וְיָנוּחַ גּוּפוֹ כְּדֵי שֶׁלֹּא יֶחֱלֶה, וְלֹא יוּכַל לַעֲבֹד אֶת ה' וְהוּא חוֹלֶה--נִמְצֵאת שִׁינָה שֶׁלּוֹ, עֲבוֹדָה לַמָּקוֹם בָּרוּךְ הוּא
Even during sleep, if one retires with the intention of resting his mind and body, lest he take ill and be unable to serve God because he is sick, then sleep is service to God.We tend to think of ritual -- tefillah / prayer, holiday observances, dietary laws, etc. -- as being the path through which we seek holiness. But Rambam's point is that everything that we do, even something as passive as sleep, can bring us closer to the Divine, if we make it so.
Rabbi Seth Adelson
Mishneh Torah, Hilkhot De'ot 3:2-3