On Chanukah , there are two Mitzvot that we perform. One is the Mitzvah of Nerot Chanukah , and the second is Kri’at Hallel.  It makes sense that there are two Mitzvot to commemorate the two miracles that happened on Chanukah . The miracle of the Menorah and the oil lasting for eight days is commemorated by lighting the Chanukahcandles, and the victory in the battle against the Yevanim is commemorated by saying Hallel. Chazal tells us in the Gemara in Megillah that we say Hallel when we are saved through a miracle. As great as the miraculous events of the Menorah were, these events are not the cause of us saying Hallel. Only the events of the war against the Yevanim which led to the Chanukaht Beit HaMikdash could warrant saying Hallel. 

The Gemara in Ta’anit on 28b explains why on Succot we say the complete Hallel every day, but on Pesach we say short Hallel after the first day. The Gemara says the reason for this distinction is that each day of Sukkot is a separate Yom Tov, because each day there are different Karbanot brought. However, on Pesach the same Karbanot are brought each day, meaning the entire week of Pesach is considered one Yom Tov. Therefore, once a full Hallel is said on the first day, there is no need to repeat it on the subsequent days. Tosafot raises the problem that if this is true then we should only say full Hallel on the first day of Chanukah . Why do we view each day of Chanukahas a separate Yom Tov and say a complete Hallel each day? Tosafot answers that the miracle of the oil was renewed each day and since each day was a new miracle we commemorate each day with a complete Hallel. This answer of Tosafot is difficult because the recitation of Hallel relates to the victory in the war against the Yevanim. Why is the fact that the miracle of the oil was renewed each day relevant to Hallel? It would make more sense to say that since we were only saved once in the war, we should only say full Hallel once. 

Although it would appear that the two miracles of Chanukahare different from one another, Tosafot obviously sees them as one. To explain this, we need to understand the battle of the Chashmona’im and the Yevanim a little deeper. The battle was fought on two different fronts. There was the physical battle fought on the battlefield between the armies, and there was the spiritual battle about the ways of life, between the impure way of life of the Yevanim and the devotion of the Chashmona’im to Torah. This idea is highlighted in Al HaNissim, where we not only mention the victory of the war, but also the Temei’im BeYad Tehorim. After the war, it was clear that the Chashmona’im won the physical war, but it was not as clear who won the spiritual war between Torah and Yavan. Rabbi Sobolofsky explains that Hashem performed a second miracle to prove that the Chashmona’im had won the spiritual war. The Gemara associates the light of Torah with the light of the Menorah and Rabbi Sobolofsky explains that if the pure oil could burn for eight days despite the fact that the Beit HaMikdash was desecrated by the Yevanim, then it was clear that the pure light of Torah had emerged from the spiritual battle with Yavan. 

This explains our question of why each day we recite a new Hallel if the miracle of the  battle, not the oil, is the reason that we say it. The answer is that the miracle of the oil was not distinct from the miracle of the battlefield, but it was the completion of the physical battle that occurred. Lighting the Menorah in the Beit HaMikdash was not just a Mitzvah being done, it was the sign of victory in the spiritual war. Being saved from spiritual death does warrant saying Hallel, just like physical victory would. Therefore, our recitation of Hallel on Chanukahcelebrates both aspects of Chanukah . Although the physical battle would allow us to say full Hallel once, the spiritual victory exhibited by the lighting of the Menorah is what requires us to say a new Hallel each day.