Who knows twenty-four?
Please cite/link your sources, if possible. After about one business day, I will:
Upvote all interesting answers.
Accept the best answer.
Go on to the next number.
24 things that push salvation farther off and make the time necessary to reach the end of days longer ...
(Braisa DiYishua SheBiPirkei D'Rabi HaKadosh)
I found a link, but it is a give-away to one of my favorite sources! :-)
24 are the divisions (mishmaros) of Kohanim, each of which served in the Beis Hamikdash for one week.
Correspondingly, there were also 24 divisions of Levi'im, and 24 groups (ma'amados) of Yisraelim who represented the rest of the people in being present at the daily Tamid sacrifices.
24 books in Tanakh
24 leniencies of Beis Shammai that are stringencies of Beis Hillel. (Tosefta, Eduyos, Chapter 2, see also Pirush HaRaavad there, Chapter 5)
The letters engraved into the luchot cut through from one side to the other. The holes in the center of the letters Mem and Samech (ם & ס) were held up by a miracle. This occurs 24 times on each side of the luchot (& only in the first five commandments). (Parshat Yisro)
24 traits to acquire the Kehuna (Avot 6:6)
24 places that Kohanim are called Leviim.
24 birds that are Tamei (Hulin, 63)
24 limbs for which a (male) Canaanite slave is set free if his owner cuts them off (Rashi on Shmot 21:27; Kiddushin 25a)
24 guarding posts in the Beis HaMikdash (3 guarded by the Kohanim and 21 by the Leviim)
(Beginning of Tractate Tamid)
24 Korbanos brought on Shavuos (3 bulls, 3 rams, 14 sheep, 2 sheep of the two breads, and 2 goats) (Lev. 23 and Num. 28)
24 decorations for a Kallah (bride) written in Yeshayah (Perek 3)
corresponding to the
24 verses mentioned in Tractate Shabbos (which is called Kallah)
(Midrash Rabbeinu Bachya, Ki Sisa)
24 Avos Nezikin
24 days when Shofar is blown during the month of Elul (for those customs that start on Elul 1 and end before Elul 29.)
It does not matter which day of the week Rosh Hashannah occurs. Eliminate the Shabbatot and the 29th of Elul (Shofar is not blown on Erev Rosh Hashanna.) It's always 24.
24=4! possible permutations for the order of havdala (wine, spice, fire, havdala; YKNH on Y"T M"S)
24 Chapters of tractate Shabbos
TWENTY FOUR is the number of letters in the longest name mentioned in Tanach.
(פלא יועץ אל גבור אבי עד שר שלום (ישעיהו ט` ה
When Achashverosh stuck out his "Sharvito" to Esther according to some sources it extended 24 Amos (Megila 15:2)
Twenty four is the number of times the word הללוי-ה appears in the Tanach, the majority of the appearances occurring in the later chapters of Sefer Tehillim.