Taken from Hegyonei Halacha

Rav Meir Don Plotzky, in his work Kli Chemdah, deals with this answer of the Taz. He begins by stating that the oil used in the menorah had to be pure olive oil, while the oil used in the miracle of Chanukah was not pure oil crushed from olives by rather was "miracle oil." Even so, what is wrong with such oil? We know from other cases that things that are created through miracles are not subject to Torah law. As proof, he refers to the Radak's commentary on II Kings 4:7, in the case where Elisha causes the oil pitcher of the poor woman to overflow. According to Radak, she asked whether or not she had an obligation to separate the appropriate tithes from this oil. Elisha responded that she had no such obligation, as her oil had come from heaven. Returning to our case, how were the Chashmonaim able to light the menorah with the oil that constantly renewed itself if that oil was not fit to be used for a mitzvah? In answer to this question, Rav Shlomo Yoseif Zevin quotes Rav Chaim of Brisk who claims that the miracle was not in the quantity of the oil, but rather in its quality. Somehow, the oil took on a certain strength by way of which only one-eighth of the normal amount was needed each night to keep the menorah lit. This answer suffices for now to answer our two questions: we celebrate eight nights because the miracle did in fact begin on the first night, and there was no problem with using "miracle oil," as the oil itself was the same oil that was present from day one, only it had been made stronger.

Two miracles occurred on Chanukah - the miracle of the oil and the miracle of the military victory. Interestingly, the two places where these occurrences are recorded have very different approaches. The gemara in Shabbat 21b that serves as our main source for the laws of Chanukah stresses the miracle of the oil, and only as an afterthought does it mention in passing that the Chashmonaim managed to prevail in battle over their enemies. In contrast to this, the text of the Al HaNissim that we add into Shemoneh Esrei and Birkat HaMazon on Chanukah places a heavy emphasis on the military victory, with only a passing reference to the miracle that occurred in the Temple. Why is this so?

Before we answer this question, we will add in a few more. The Maharal points out that according to the gemara in Shabbat, the main reason that it was established to recite Hallel on Chanukah was due to the miracle of the oil. He asks why this is a reason to say Hallel. We know that a person who is saved from danger has an obligation to thank Hashem (such as the four types of people who must say birkat hagomel - one who was ill, one who was released from prison, one who crossed a desert, and one who crossed and ocean), but where do we ever see a case of a person being obligated to thank Hashem (in any official way) merely because he is now able to perform a mitzvah that until now he was unable to do? The Pnei Yehoshua asks a further question - why was any miracle needed with regard to the oil? True, in general pure olive oil was needed. However, we know that with regard to the Korbon Pesach, if a majority of the nation was impure the sacrifice was brought anyway, as we have a principle that "tumah hutrah b'tzibbur" - that impurity is permitted on a public level (i.e. when a majority of the public is impure). This being the case, why could they not have lit the menorah with the impure oil that they had, seeing as most of the nation was impure anyway (both from coming into contact with dead bodies in battle and, presumably, from not having had any way to purify themselves due to the fact that the Temple had been "closed for business")?

Our answer begins with the Maharal. He states that in reality, the main miracle of Chanukah is that of the military victory. However, there is a danger inherent in having a holiday that celebrates such an event. It is too easy, over time, for people to remember only the military aspect of the victory, and gradually to forget the fact that it was Hashem who enabled the Jews to prevail over their enemies. Thus, the miracle of the oil occurred, as if to remind the people that the real essence of the miracle was not one of brute force but rather one of quality. Just as the quality of the oil increased to allow it to burn for eight days, so too the quality of the Jews increased to allow them to be victorious in battle. That is what is stressed in the text of the Al HaNissim, the idea that the Jews were inferior in every way, yet managed to defeat the Syrian-Greeks.

This answer can now solve all of our problems. First, with regard to the question of the Maharal, we see that, in fact, there is not a holiday of thanks as a result of being able to once again perform a mitzvah. The holiday is actually established due to the military victory, which certainly does require that one give thanks, and the miracle of the oil comes along merely to highlight the miracle aspect of that victory. The question of the Pnei Yehoshua is thus answered as well. As far as the law itself was concerned, there really was no problem with lighting the menorah with impure oil. However, the entire point of the miracle of the oil was not so that there would be oil, but rather so that there would be a lasting testimony to the involvement of Hashem in the entire story of Chanukah. Finally, why the gemara does not stress the military aspect is now apparent as well. The question asked in the gemara is "what is Chanukah?" This question aims at understanding the real essence of the holiday, an essence that is encapsulated in the miracle of the oil. The gemara seeks to prevent people from mistaking the true source of the overall victory of Chanukah, and thus it stresses the oil, while Al HaNissim does not have this as its agenda, and thus it stresses the military victory, and not the oil.

This idea can also serve to explain the last line of the gemara. It states that in the year following the victory the Sages established these days as a holiday. Why did they wait an entire year before doing so? It would seem that they understood the nature of the people. They knew that there would be a danger of the people misattributing the victory by failing to recognize the hand of Hashem. Thus, they first allowed the news of the miracle of the oil to spread and to become firmly entrenched in the minds of the people. Only after that had occurred did they establish a holiday that also included a remembrance of the military victory.