Chanukah is never written outright in the Torah (probably because the Chanukah story happened approximately 164 B.C.E., over a century after the death of Moshe Rabbeinu ZT”L), but there are many hints to it. Here are some of them:
The twenty-fifth word of the Torah is the word “Or,” “Light” (BeReishit 1:3). This hints to the lights that we light every year starting on the 25th day of Kislev.
In Parashat Masei, when recounting the places Bnei Yisrael camped, the twenty-fifth place they stopped was Chashmona. This hints to the Chashmona’im who fought in the battle of Chanukah, and rested from fighting on the twenty-fifth of Kislev.
The commandment to light the Menorah is juxtaposed with all the Chagim in Parashat Emor. This hints that there is a holiday connected to lighting the Menorah.
Ramban comments on the juxtaposition of the Chanukat HaMishkan and the instructions to Aharon on how to light the Menorah. He says that Aharon complained that his Shevet, Shevet Levi, was not able to participate in the Chanukat HaMishkan. Hashem consoled him by saying that the Chanukat HaMishkan happened only once, but the commandment to light the Menorah will happen every day in the Mishkan, and then in the Beit HaMikdash, and then even after the Churban Bayit, every year on Chanukah (Ramban BeMidbar 8:2 s.v. BeHa’alotecha, explaining Rashi).
The last word in Parashat Terumah is “Nechoshet,” “copper” (Shemot 27:19). The next Pasuk, the first Pasuk in Parashat Tetzaveh, is “Ve’Atah Tetzaveh Et Bnei Yisrael YeYikchu Eilecha Shemen Zayit Zach Katit LaMa’or LeHaalot Neir Tamid,” “You shall further instruct the Israelites to bring you clear oil of beaten olives for lighting, for kindling lamps regularly” (ibid. 20). What is the connection between copper and the commandment to make oil for the Menorah? Here are are two answers. The Bnei Yissaschar explains that this is connected to a story in Daniel. Nevuchadnetzar had a dream of a figure with a gold head, silver arms, copper stomach and thighs, and iron legs. The figure then crumbled. Daniel interpreted the dream to mean that the figure represented the four nations who conquered the Jews: the golden head was Nevuchadnetzar and the Babylonians, the silver arms were the Persians, the copper stomach and legs were the Greeks, and the iron legs were Rome. All these nations crumbled before Hashem. The Pasuk was hinting to us that because of the Greeks, Nechoshet in Daniel’s dream, there would be a special need to prepare oil for the Menorah. The Mateh Moshe, along with the Rokeach and the Hagahot Mordechai HaChadash says that the word Nechoshet is actually an acronym for some of the Halachot of Chanukah. Nechoshet stands for “Neir Chanukah Sham Tadliku,” “Neir Chanukah Semol Tadlik,” and “Neir Chanukah Shamash Tadlik”. Nechoshet is reminding us that no matter where we are (Sham), we are supposed to light the Menorah on the left of the door (Semol), and with a Shamash.
These are just some of them of the allusions in the Torah, but there are many more. Chag Sameiach!