One performs a mitzvah at the highest level when it is done with all of one’s heart and soul. 

Perhaps the first Torah source which expresses this idea is found in the Shema:
 וְאָ֣הַבְתָּ֔ אֵ֖ת יְהֹוָ֣ה אֱלֹהֶ֑יךָ בְּכׇל־לְבָבְךָ֥ וּבְכׇל־נַפְשְׁךָ֖ וּבְכׇל־מְאֹדֶֽךָ (דברים ו:ה)

 You shall love the LORD your God with all your heart and with all your soul and with all your might. (Devarim 6:5)

The Rambam speaks of the particular love that the Jew has when lighting the menorah.It is rare that the Rambam speaks of a mitzvah in this way. Look how far one needs to go in order to fulfill the mitzvah.
משנה תורה, הלכות מגילה וחנוכה ד:יב

מִצְוַת נֵר חֲנֻכָּה מִצְוָה חֲבִיבָה הִיא עַד מְאֹד וְצָרִיךְ אָדָם לְהִזָּהֵר בָּהּ כְּדֵי לְהוֹדִיעַ הַנֵּס וּלְהוֹסִיף בְּשֶׁבַח הָאֵל וְהוֹדָיָה לוֹ עַל הַנִּסִּים שֶׁעָשָׂה לָנוּ. אֲפִלּוּ אֵין לוֹ מַה יֹּאכַל אֶלָּא מִן הַצְּדָקָה שׁוֹאֵל אוֹ מוֹכֵר כְּסוּתוֹ וְלוֹקֵחַ שֶׁמֶן וְנֵרוֹת וּמַדְלִיק:

The precept of lighting the Hanukkah lamp is exceedingly precious, and one should carefully observe it in order to acclaim the miracle, ever praising and thanking God for the miracles which he has performed for us. Even if one has nothing to eat except what he gets from charity, he should borrow, or sell his garment, to buy oil and lamps and light them. (Mishneh Torah , Hilchot Megillah and Chanukah 4:12)