"Ha-Neirot halalu" - What Does It Mean, Why Is It Said and Who Instituted It?"

The Festival of Hanukka is a rabbinic institution, fashioned by the Rabbis after the events of the second century, B.C.E. (See below.) It is the only festival not cited in Tanakh.
The Poskim were very aware of this difference, yet when we examine the laws and practice of Hanukka, we observe a gradual development to make Hanukka a "real" festival. Laws, restrictions and requirements were formulated to enhance the standing of Hanukka.

Here's a small point, but one that illustrates this trend.

שולחן ערוך, אורח חיים רל״ו:ב׳

(ב) אין לספר בין גאולה דערבית לתפלה.... ומיהו מה שמכריז ש"צ "ר"ח" בין קדיש לתפלת ערבית, לא הוי הפסק כיון שהוא צורך תפלה.

Shulchan Arukh, Orach Chayim 236:2

(2) One should not talk between the blessing about redemption (ge'ulah) in the evening and the Amidah.... What about when the reader announces Rosh Chodesh [so people can remember to say ya'aleh ve'yavo] between Kaddish and the evening Amidah? This is not a pause, since it is a requirement for the Amidah....

Magen Avraham (R.Avraham Gumbiner, d.1682, Poland) to this law (O.C. 236):

Tzורך תפלה. ....ומ"מ אפשר דוק' בר"ח שהיא דאורייתא או ב"ותן טל ומטר" דמחזירין אותו אם לא אמרו, משא"כ בחנוכה ופורים שאין מחזירין אותו אם לא אמרו, אפשר שאין מכריזין ומ"מ המנהג להכריז.

The talmudic citation of the festival of Hanukka occurs in the second chapter of Shabbat, a chapter which deals with the Shabbat light. All of a sudden, various pages of Gemora interrupt the sugyot (cases) and Hanukka is discussed. Shabbat 21b states:

מַאי חֲנוּכָּה? דְּתָנוּ רַבָּנַן: בְּכ״ה בְּכִסְלֵיו יוֹמֵי דַחֲנוּכָּה תְּמָנְיָא אִינּוּן דְּלָא לְמִסְפַּד בְּהוֹן וּדְלָא לְהִתְעַנּוֹת בְּהוֹן.
שֶׁכְּשֶׁנִּכְנְסוּ יְוָוֽנִים לַהֵיכָל טִמְּאוּ כׇּל הַשְּׁמָנִים שֶׁבַּהֵיכָל. וּכְשֶׁגָּבְרָה מַלְכוּת בֵּית חַשְׁמוֹנַאי וְנִצְּחוּם, בָּדְקוּ וְלֹא מָצְאוּ אֶלָּא פַּךְ אֶחָד שֶׁל שֶׁמֶן שֶׁהָיָה מוּנָּח בְּחוֹתָמוֹ שֶׁל כֹּהֵן גָּדוֹל, וְלֹא הָיָה בּוֹ אֶלָּא לְהַדְלִיק יוֹם אֶחָד. נַעֲשָׂה בּוֹ נֵס וְהִדְלִיקוּ מִמֶּנּוּ שְׁמוֹנָה יָמִים. לְשָׁנָה אַחֶרֶת קְבָעוּם וַעֲשָׂאוּם יָמִים טוֹבִים בְּהַלֵּל וְהוֹדָאָה.

שבת כ״א ב

Shabbat 21b

The Gemara asks: What is Hanukkah? The Sages taught [in Megillat Ta’anit:] On the twenty-fifth of Kislev, the days of Hanukkah are eight. One may not eulogize on them and one may not fast on them.

When the Greeks entered the Sanctuary they defiled all the oils that were in the Sanctuary by touching them. And when the Hasmonean monarchy overcame them and emerged victorious over them, they searched and found only one cruse of oil that was placed with the seal of the High Priest, undisturbed by the Greeks. And there was sufficient oil there to light the candelabrum for only one day. A miracle occurred and they lit the candelabrum from it eight days. The next year the Sages instituted those days and made them holidays with recitation of hallel and special thanksgiving in prayer and blessings.

This source demonstrates the complexity of Hanukka: why was it instituted? This passage is the only reference to a "miracle" of light. It is not found in either Talmud.

The main ritual is the lighting of a lamp, over which various blessings are recited. After the blessings, a prayer is recited.

The only source for this prayer is (probably) Tractate Sofrim.

M. Sofrim is not part of the Mishna, nor is it in the Babylonian or Palestinian Talmuds. It is a collection of laws dealing with the writing of holy texts as well as the liturgy and observances of many festivals. It was probably composed in Israel during the Geonic period in the 8th century. (In many printed editions of the Talmud it is printed in the back of the Talmud volumes of Avoda Zara or Sanhedrin, with other smaller non-mishnaic tractates.)
Al HaNissim is found in Sofrim, ch.20. It first describes various blessing recited over the Lights, then it says:

מסכת סופרים כ׳

...ואומר: "הנרות האלו אנו מדליקין על הישועות ועל הניסים ועל הנפלאות אשר עשית לאבותינו ע"י כהניך הקדושים. וכל (מצות) שמונת ימי חנוכה, הנרות האלו קודש ואין לנו רשות להשתמש בהן אלא לראותן בלבד, כדי להודות לשמך על נפלאותיך ועל נסיך ועל ישועתך.

בא"י שהחיינו ואומר שעשה נסים לאבותינו...."

Tractate Soferim 20

....

Then he says, ‘We kindle these lights on account of the deliverances and the miracles and the wonders which Thou didst work for our fathers, by means of Thy holy priests. During all the eight days of Ḥanukkah these lights are sacred, and it is not permitted to make any profane use of them but we are only to look at them, in order that we may give thanks unto Thy name for thy wonders, Thy miracles and Thy deliverances’.

[The third benediction is] ‘Blessed art Thou, O Lord, Who hast kept us in life’. [Before this] he says, ‘Who wroughtest miracles for our fathers’.

The problem: This prayer is rather universally recited after lighting the candles. Its source seems to be Sofrim; it is not referred to in the Talmud, Rambam, Rif or in most of the Geonic literature.
Why and when did it become so important; what is it about?

R. David Avudarham composed an important work about prayer (c/1340; Seville, Spain) which influenced Rav Yosef Karo, as well as later authorities. He states the following regarding the Hanukka lighting:
"(א)סדר תפלות חנוכה

(ב) חייב כל איש ישראל להדליק נר
(י)ואמרי' במסכת סופרים המדליק נר חנוכה אחר שהדליק אומר "הנרות הללו אנו מדליקין...." וכן היו נוהגין לומר הר' מרוטנבורק והרא"ש.
והמון העם אינם אומרים "ואחר כך באו בניך וכו'." ונכון לאומרו כי הוא עיקר הנס....
"כשם שעשית עמהם פלא, כן עשה עמנו וכו'" כתב הרב ר' מאיר מרוטנבורק שאין ראוי לומר "כשם שעשית עמהם פלא ונס," לפי שאין ראוי לומ' תפלה בהודאה.
ויש אומריםכיון שהוא צורך רבים יכולין לאומרו כמו שאומר בהודאה, "וכתוב לחיים טובים" שהוא תפלה, וגם בברכת אשר גאלנו של ליל פסח שהיא הודאה אומר "כן יגיענו יהוה אלינו למועדים וכו'," וגם במודים דרבנן אומר "כן תחיינו ותחננו ותאסוף גליותנו....

It seems that the inclusion of Ha-Neirot Ha-lalut as an essential prayer on Hanukka was an enactment of Rav Meir of Rothenburg. He added it because its states that one may not use the Menorah for non-ritual purposes. "We are not permitted to use it; we may only look at it...."

The debate about the use of the Menorah goes back to the Talmud (Shabbat 22a); we here encounter a major dispute between the leader of Ashkenazic Jewry, Maharam Rothenberg, and Provencal authorities. They permitted its use whereas the Maharam forbade it, which is stated in Ha-Neirot Ha-lalu.

One could argue that the purpose of Ha-Neirot Ha-lalu was to give the Menorah standing that, in a sense, makes it comparable to the Menorah in the Temple. By reciting this formula, we advance Hanukka from a historic re-enactment to, so to speak, a re-creation of the Temple and its appurtenances. It elevates the Menora and the Festival to make it quasi-biblical in importance.

Thus, Rosh (R.Asher, pupil of R. Meir Rothenburg, who moved from Germany to Spain), wrote (Shabbat, section 9) that according to R.Ahai, author of the (geonic) Sheiltot, that when Hanukka concludes, one should burn up all the oil left in the Menorah, "since it was set aside ("hukza") for a mitzva, one is prohibited from using it." He declares that the Menora has become exclusively designated for its ritual - "huktza l'mitzvata" - and has to be treated accordingly.

שבת כ״ב א

אָמַר רַב יְהוּדָה אָמַר רַב אַסִּי אָמַר רַב: אָסוּר לְהַרְצוֹת מָעוֹת כְּנֶגֶד נֵר חֲנוּכָּה. כִּי אַמְרִיתַהּ קַמֵּיהּ דִּשְׁמוּאֵל, אָמַר לִי: וְכִי נֵר קְדוּשָּׁה יֵשׁ בָּהּ? מַתְקֵיף לַהּ רַב יוֹסֵף: וְכִי דָּם קְדוּשָּׁה יֵשׁ בּוֹ? דְּתַנְיָא ״וְשָׁפַךְ … וְכִסָּה״ — בַּמֶּה שֶׁשָּׁפַךְ יְכַסֶּה. שֶׁלֹּא יְכַסֶּנּוּ בָּרֶגֶל, שֶׁלֹּא יְהוּ מִצְוֹת בְּזוּיוֹת עָלָיו. הָכָא נָמֵי, שֶׁלֹּא יְהוּ מִצְוֹת בְּזוּיוֹת עָלָיו.

Shabbat 22a

Rav Yehuda said that Rav Asi said that Rav said: It is prohibited to count money opposite a Hanukkah light.Rav Yehuda relates: When I said this before Shmuel, he said to me: Does the Hanukkah light have sanctity that would prohibit one from using its light? Rav Yosef strongly objected to this question: What kind of question is that; does the blood of a slaughtered undomesticated animal or fowl have sanctity? As it was taught in a baraita that the Sages interpreted the verse: “He shall spill its blood and cover it with dust” (Leviticus 17:13): With that which he spilled, he shall cover. Just as a person spills the blood of a slaughtered animal with his hand, so too, he is obligated to cover the blood with this hand and not cover it with his foot. The reason is so that mitzvot will not be contemptible to him. Here too, one should treat the Hanukkah lights as if they were sacred and refrain from utilizing them for other purposes, so that mitzvot will not be contemptible to him.