Who knows twenty-five?
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25 is the year Yehezkel prophesied the 3rd Temple. In said Temple, the gate was 25 amot wide, and there were 25 steps up to the heikhal.
25 are the stops of the Israelites in the desert when they reached "Chashmonah." Which echoes of Chanukah.
25 is the number of letters (making up the names of six of the tribes) on each of the shoham (onyx?) stones on the shoulder straps of the Kohen Gadol's efod (apron). (Ex. 28:9ff; Rambam, Hil. Klei Hamikdash 9:9)
25 limbs for which a (female) Canaanite slave is set free if her owner cuts them off (Rashi on Shmot 21:27; Kiddushin 25a)
25 is the number of people in the family of R' Akiva of Ofen (himself, twelve sons, and twelve sons-in-law) who used to recite the Priestly Blessing together. R' Akiva used to say that he was thereby fulfilling the Torah's commandment, "Thus (כה - equals 25) shall you bless the Children of Israel...."
25 are the letters in "Shema Yisrael Hashem Elokeinu Hashem Echad", mirrored by the 25 letters in "Baruch Shem Kvod Malchuso L'Olam Va'ed." The two Shoham stones represent Hashem Echad on one side, U'Shmo Echad on the other side. All that's left is to connect it to the Choshen HaMishpat, which is needed to keep the Jewish people together as one!
(Adapted from the Malbim's essay "ramazei haMishkan.")
25 is the age at which Levi'im are counted and begin their service in the Temple. They then served for 25 years.
25 was the age of Chizkiyahu when he began to rule.
25 years is the statute of limitations for a widow or her heirs to collect a ketubah in certain circumstances. See Ketubot 104a.