Why should one celebrate the dedication of the OLD TEMPLE when NOW WE ARE THE NEW TEMPLE OF THE SET-APART SPIRIT, the real one?
ANSWER:
While the physical tabernacle or Temple is a sign of Yahweh's presence among His people, we believe that Yahweh has always dwelt in the hearts of His true followers. "And I will dwell amongst the children of Yisrael, and will be their Elohim. And they shall know that I am Yahweh their Elohim, that brought them forth out of the land of Mitzrayim, that I may dwell amongst them: I am Yahweh their Elohim." (Exodus 29:45-46) The physical tabernacle / Temples have always pointed to the fact that Yahweh desires to dwell amongst His people and in the hearts of those who truly desire to serve Him. "Behold, thou desirest truth in the inward parts, and in the hidden parts Thou shalt make me to know wisdom." (Psalm 51:6) What is truth? "Thy Word is truth." (John 17:17) Who is the living Word? "In the beginning was the Word and the Word was with Elohim, and the Word was Elohim." (John 1:1) Yahweh the Son (Yahshua, the living manifestation of Yahweh) is the embodiment of the Word, and He is perfect truth. What is wisdom? Wisdom is compared to a living being dwelling with (or as part of) Yahweh from before the beginning of time. (Proverbs 8) Again, in the Apocryphal writings we see an indication that Wisdom is an allegorical way of referring to the set-apart Spirit of Yahweh. "For into a malicious soul wisdom will not enter, nor dwell in the body that is subject unto sin. For the set-apart Spirit of discipline will flee deceit, and remove from thoughts that are without understanding, and will not abide when unrighteousness cometh in. For Wisdom is a loving Spirit, and will not acquit a blasphemer of his words, for Elohim is a witness of His reigns, and a true beholder of his heart, and a hearer of his tongue. For the Spirit of Yahweh filleth the world, and that which containeth all things hath knowledge of the voice." (Wisdom of Solomon 1:4-7) So if we look closer at Psalm 51, we can actually gather from verse 6 that David is saying that Yahweh our Salvation (the living Word; the complete embodiment of truth) and the set-apart Spirit of wisdom desires to dwell within us. This is not a "New Testament" thing. Yahweh has always wanted to dwell in His people's hearts. Individuals seeking after Yahweh have always been the true Temple towards which the physical tabernacle / Temples have pointed. The sad thing is that only a small majority of mankind has granted Yahweh admittance into their hearts. This is the way it has always been, and it is no different today. Yahshua's life and death on earth did not change the fact that people's hearts are hard, and that most will not hear Him. "If they hear not Moshe and the prophets, neither will they be persuaded though One rose from the dead." (Luke 16:31) The majority of humanity, past and present and future, is "closed down" to Yahweh's truth. A small minority, however, has always allowed Yahweh to place His Name in their hearts and lives and set them apart unto Himself.
I am just laying the foundation that we believe the "real" Temple as you say, the Temple of the set-apart Spirit, has always been dedicated individuals seeking Yahweh's ways -- before the tabernacle, during the tabernacle, before the Temple, during the Temple times, and yes, even now today!
As far as why we celebrate the dedication. Something that is not often considered is that the Maccabees Chanukah (dedication) celebration was not the first Chanukah celebration ever kept. Numbers 7 uses the word "chanukah" (verse 10, 84) and gives a detailed account of the 12-day dedication feast that was kept for the altar at the completion of the tabernacle being set up and anointed and set apart. Again, in 1 Kings 8, the house of Yahweh was dedicated / chanukah-ed (verse 63). In Shlomo's prayer at the dedication of this Temple, he recognized the fact that Yahweh could not be contained in that Temple, but that He filled the heaven of heavens (verse 30). However, that Temple was a symbol of Yahweh dwelling amongst His people, and Shlomo's entire prayer at the dedication of the Temple actually dealt specifically with the people's hearts and the people's prayers, which have always been the real issue.
Once again, the real heart of the matter in 1 Maccabees was the people's dedication or lack of dedication to Yahweh. Many fell for corruption; a small remnant was dedicated wholeheartedly to Yahweh. (1 Maccabees 2:19-22) Fighting Antiochus' army and recapturing Yahweh's Temple really had hardly anything to do with a physical structure; it had to do with devotion to Yahweh's Law and covenant (1 Maccabees 2:50), even if it meant laying down one's life to do so. The Maccabees passed on a wonderful legacy to us of dedication and fidelity. Would to Yahweh that more would carry on such a legacy!
The actual dedication (it is interesting to note) was not of the Temple, but of the altar. (1 Maccabees 4:56; See also Numbers 7:10, 84)
So why should we keep Chanukah (Dedication)? We are the Temple of Yahweh (Halleluyah!), and we dedicate ourselves to Him! We look back on our Israelite history, and see how time and again, the enemy has tried to stamp out all practice of the faith delivered by Yahweh / Yahshua. And yet through it all, we see Yahweh's incredible dedication to preserving a remnant of His people. And so with joy we dedicate ourselves to Him as His dwelling places / Temples. We dedicate our own lives personally, laying them down on the altar as living (and if need be, dying) sacrifices to Him. (Romans 12:1-2) This is not something we only do for eight days in the month of Chisleu. This is something we try to do all year long, every day, every hour..... with Yahweh's help. All of the Sabbaths and Feasts call us to renewed dedication, and Chanukah is just one more reminder to stand up for what is right, to be thankful for Yahweh's dedication to us, to be willing to be different, to sacrifice our entire lives to Yahweh, to allow Him to inhabit us more fully, and to commit to greater personal dedication.
May Yahweh be esteemed!