Berachos, Chapter 8, Mishnah 5. This mishnah deals with the laws of Havdalah and with the dispute between Beis Shammai and Beis Hillel regarding the order of the berachos. In practical terms, we are dealing with a specific situation: a person has only one cup of wine before him; he has not yet recited the berachah after the third Shabbos meal and wishes to recite it over the cup, but he needs that very same cup for Havdalah as well. What, then, is the correct order of the berachos he should recite?
The dispute between Beis Shammai and Beis Hillel regarding the order of the berachos:
"Beis Shammai omrim: ner u'mazon u'vesamim v'Havdalah" - first he recites "borei me'orei ha'eish," then the berachah after the meal, then "borei minei vesamim" over the spices, and finally Havdalah - all of this over a single cup of wine.
"U'Beis Hillel omrim: ner u'vesamim u'mazon v'Havdalah" - Beis Hillel agrees that the candle comes first, but holds that the spices are blessed immediately afterward, and only then the berachah after the meal, with Havdalah last.
Beis Hillel wishes to group the candle and the spices together, since both relate to the conclusion of Shabbos. As the Rambam writes, a person's soul grieves over the departure of Shabbos, and we gladden it with a pleasant fragrance; and the candle - because fire was first created at the conclusion of Shabbos.
The opinion of Rabbi Yehudah in the Gemara:
The Gemara explains that the way the dispute is presented in our mishnah follows the view of Rabbi Meir. Rabbi Yehudah, however, holds that both Beis Shammai and Beis Hillel agree that the berachah after the meal is recited first and Havdalah last, and their entire dispute concerns only the order of the candle and the spices: according to Beis Shammai the candle comes first and the spices after it, while according to Beis Hillel the spices come first and the candle after them.
And the Gemara concludes: "Amar Rabbi Yochanan: nahagu ha'am k'Beis Hillel aliba d'Rabbi Yehudah" - and this is the basis for the order we follow: wine (borei pri hagafen, which is connected to the berachah after the meal), spices, candle and Havdalah, whose initials spell Yavneh.
The wording of the berachah over fire:
The mishnah brings a further dispute between Beis Shammai and Beis Hillel concerning one aspect of Havdalah - the wording of the berachah over the light:
"Beis Shammai omrim: shebara me'or ha'eish" - "bara" is past tense, and therefore the berachah refers to the original fire that was created during the six days of Creation.
"U'Beis Hillel omrim: borei me'orei ha'eish" - "borei" is present tense, like the wording of the verse "yotzer or u'vorei choshech," indicating that creation is continually renewed; and "me'orei" is plural, for as the Gemara says, "there are many lights in fire" - an allusion to the different shades within a flame: the blue portion, the white, the red and the orange.
In summary: In this mishnah we learned the order of the berachos when a person has only one cup of wine before him for both the berachah after the meal and Havdalah: the dispute between Beis Shammai and Beis Hillel regarding the order of the candle, the meal, the spices and Havdalah as presented according to Rabbi Meir, the view of Rabbi Yehudah that their entire dispute concerns only the order of the candle and the spices, and the halachah that the people follow Beis Hillel according to Rabbi Yehudah - the order of Yavneh. We also examined their dispute regarding the wording of the berachah over the light: "shebara me'or ha'eish" as opposed to "borei me'orei ha'eish."