The Two Most Important Words on Chanukah
(At first glance, this sounds superficial, but the Kli Yakar detailed how this worked in Parshat Tzav.)
In Words of Faith, Rav Levi Yitzchak Bender stresses that the Jewish soul cannot bear the weight of sin for even a day. Why?
Because the Jewish soul is so ethereal, subtle, delicate, and sacred, explains Rav Bender.
This why a daily cheshbon hanefesh is so essential -- and why it's so essential to confess your sin to Hashem even a moment after you just transgressed whatever you transgressed. (Even though doing so feels really weird. But it's genuinely helpful and the right thing to do.)
Within the Beit Hamikdash, Jews had the Chanukat Habayit ceremony -- Dedication of the House (i.e., the Temple).
So what can we do nowadays with no Beit Hamikdash & no Chanukat Habayit?
Cry out to Hashem: "Slach na -- please forgive!!!"
Rav Bender quotes Rebbe Nachman from Likutei Moharan II:2
"Know! Each one has Chanukah according to what he accomplished in his request on Yom Kippur: 'Please forgive!' "
"Vayar Hashem ki sar lirot" (Shemot 3:4)
Hashem saw that he turned to look: He gazed to see what would be at the time of Galut (Exile), the time of "sar"-- rage.
(He explains that sar can also mean "storm" -- and as far as I know "storm" is spelled with an ayin.)
Bringing Down the Power of Chanukah
סְלַח־נָ֗א לַֽעֲוֹ֛ן הָעָ֥ם הַזֶּ֖ה כְּגֹ֣דֶל חַסְדֶּ֑ךָ וְכַֽאֲשֶׁ֤ר נָשָׂ֨אתָה֙ לָעָ֣ם הַזֶּ֔ה מִמִּצְרַ֖יִם וְעַד־הֵֽנָּה
"Please forgive the iniquity of this nation in accordance with your abounding kindness, as You have borne this people from Egypt until now."
And we see from the above that this is a definite koach double-wrapped within Chanukah, which exists within Kislev, as hinted in the Torah.
Rav Bender states (Words of Faith, Vol. II, pg. 450):
"The world does not know the secret that, in place of the offerings, [you need to] scream: 'Please forgive!' The secret of Chanukah -- the Chanukas Beit Hamikdash and offerings -- yell, 'Please forgive!' "
"That just through screaming, 'Please forgive!' we can merit that Hakadosh Baruch Hu will answer and atone: 'God said, "I forgive according to your word!" ' " (Bamidbar 14:20)
"SLACH NA -- PLEASE FORGIVE!!!"
And you'll bring down blessing upon yourself and upon the Jewish people with a power that lasts throughout the entire year.