As mentioned, the Chanukah lights are kindled after sunset. Metaphorically,
“After sunset” specifically refers to the darkness of exile,1וְהִנֵּה הָעִנְיָן דְּמִשֶּׁתִּשְׁקַע הַחַמָּה קָאֵי בְּיִחוּד עַל חֹשֶׁךְ הַגָּלוּת,
and in particular to the compounded darkness of ikvesa dimeshicha, “the era when we are on the heels of Mashiach’s arrival.”וּבִפְרָט הַחֹשֶׁךְ כָּפוּל וּמְכֻפָּל דְּעִקְבְתָא דִּמְשִׁיחָא.
This is the lesson the Chanukah lights teach every person in the era of exile,וְזוֹהִי הַהוֹרָאָה דְּנֵר חֲנֻכָּה לְכָל אֶחָד וְאֶחָד בִּזְמַן הַגָּלוּת,
that the intent of the darkness of exile is to arouse the Divine service of mesirus nefesh –שֶׁהַכַּוָּנָה דְּחֹשֶׁךְ הַגָּלוּת הוּא בִּכְדֵי לְעוֹרֵר הָעֲבוֹדָה דִּמְסִירוּת נֶפֶשׁ,
Not only do the Jewish people have the power to overcome the darkness of exile by calling forth the potential of yechidah that exists within their souls, the purpose of the exile is to arouse this potential.
– and in this manner, refine the darkness of exile and transform it into light.וְעַל יְדֵי זֶה מִתְבָּרֵר הַחֹשֶׁךְ וְנֶהְפָּךְ לְאוֹר.
Through combining the Divine service of the entire Jewish people –וְעַל יְדֵי צֵרוּף עֲבוֹדַת כָּל אֶחָד וְאֶחָד מִבְּנֵי יִשְׂרָאֵל יַחַד,
or at least the majority of them (and the majority is considered as the entire people)2 –עַל כָּל פָּנִים רֻבָּם (דְּרֻבּוֹ כְּכֻלּוֹ),
and indeed, even one mitzvah performed by any individual Jewוַאֲפִלּוּ עַל יְדֵי מִצְוָה אַחַת שֶׁל אֶחָד מִיִּשְׂרָאֵל,
whether in deed, speech, or thoughtהֵן בְּמַעֲשֶׂה הֵן בְּדִבּוּר וְהֵן בְּמַחֲשָׁבָה,
tips the scales of one’s individual balance and the balance of the entire world to good, bringing himself – and humanity as a whole – deliverance and salvation.3הוּא מַכְרִיעַ אֶת עַצְמוֹ וְאֶת כָּל הָעוֹלָם כֻּלּוֹ לְכַף זְכוּת וְגוֹרֵם לוֹ וְלָהֶם תְּשׁוּעָה וְהַצָּלָה.

Summary

The Chanukah lights are kindled after sunset. Metaphorically, “after sunset” specifically refers to the darkness of exile. The Chanukah lights teach everyone that the intent of the darkness of exile is to arouse the Divine service of mesirus nefesh. Through that service, the darkness of exile is refined and transformed into light.