Introduction to the Trei Asar
The Gemara Bava Basra 14b tells us that the recorded prophecies of twelve prophets were put together as one book to preserve them: the risk of seeing them lost if they were ‘cast’ as twelve small individual books was too great. They were bound together in one large scroll called the Trei Asar. The Trei Asar are: Hoshea, Yoel, Amos, Ovadiah, Yonah, Micha, Nachum, Chabakuk, Tzefania, Chaggai, Zecharia and Malachi. These are not Neviim who prophesied during the same period. Chaggai and Malachi lived during the final period of the Neviim, at the time of the second Beis Hamikdash (after the Purim story), and Chaggai was a member of the Anshei Kenesses Hagdolah who fixed our prayer texts. Yet Hoshea’s prophecy preceded that of Yeshaya (well before the destruction of the first Mikdash). Thus, our Trei Asar prophets span over 350 years - from the middle of the First Temple to the early years of the Second Temple.
Hoshea
Hoshea was a prophet during the times of the first Beis Hamikdash. He prophesied for 90 years and was a contemporary of Yeshaya, Amos, and Micha. The Gemara (Pesachim 87a) records that Hoshea was a greater prophet than his contemporaries (even greater than Yeshaya, a significant praise in light of the Malbim’s parallels between Yeshaya and Moshe Rabbeinu). The Radak describes Hoshea as a Sefer primarily containing ‘Words of rebuke towards Bnei Yisrael and Yehuda after their disloyal behavior to Hashem”.
Yoel
There is some mystery surrounding when Yoel lived. According to the Midrash (Bamidbar Rabbah 10:5) quoted by Rashi at the start of Yoel, Yoel was actually the son of Shmuel Hanavi. And though he is called ‘son of Petuel,’ this is merely a form of acronym for the fact that his prayer was effective (pittah Kel be’tfillaso). Yoel prophesied during the days of Yehoram ben Achav in the era of the first Beis Hamikdash (over 300 years before its destruction). However, in the Seder Olam, Yoel is listed as prophesying during the days of Menasheh, son of Chizkiyah (50 years before the churban), and as such, was the disciple of Micha the prophet.
Yoel first prophesies about the forthcoming plague of locusts and ensuing famine, and then speaks about forthcoming blessing and the days of Moshiach.
Amos
Amos, a shepherd according to the Radak, was a student of Hoshea and lived in the same generation as Michah, Yeshaya, and Hoshea. The Gemara (Pesachim 87a) tells us that Amos prophesied after Hoshea. Amos was a prophet during the times of Uziyah king of Yehuda, and Yeravam ben Yoash king of Yisrael (approximately 100 years before the exile of the ten tribes, and approximately 250 years before the destruction of the first Beis Hamikdash). During the times of Amos, Bnei Yisrael enjoyed wealth and tranquillity: the surrounding nations would even pay them taxes. However, this wealth was requisitioned by the ‘Jewish nobility’. The Seder Hadoros writes that Amos was killed by Uziyahu king of Yehuda.
Some of the prophecies of Amos are directed at the nations of the world, and others are directed at Bnei Yisrael, warning them about the transience of their current material success and tranquillity. The Radak explains that the structure of Sefer Amos is straightforward. First, Amos denounces the nations for their barbarism, and then he turns to Bnei Yisrael to reproach them for their failures.
Ovadiah
Ovadiah was a convert who was a student of Eliyahu Hanavi. He prophesied during the era of Yehoshafat king of Yehuda, and Achav king of Yisrael (only 60 years after the division of the kingdom, and 300 years before the destruction of the first Beis Hamikdash). Ovadiah was a contemporary of Elisha, Yona, and Michayahu. He lived in the kingdom of Yisrael under the reign of king Achav and his wife Izevel. The Gemara (Sanhedrin 39b) reports that even though converts tend not to be prophets, Ovadiah merited prophecy as a result of his mesirus nefesh in putting his life in danger for the sake of Klal Yisrael; he hid (and provided for) one hundred prophets in a cave to save them from king Achav (who was on a killing spree against the prophets). Ovadiah was very wealthy and was in charge of Achav’s household. Ovadiah’s prophecies are about Edom, his own nation, before he converted.
One could ask why Ovadiah's prophecy about Edom was recorded in Tanach; surely Edom did not hear this prophecy?! One can put forward three answers. First, the very knowledge that Hashem punishes nations increases our faith in His justice. Second, this verifies and strengthens our belief in prophecy[1]. Third, the Ran in his Drashos notes that a punishment for the other nations serves as a warning (hasra'ah) to Bnei Yisrael to wake up and repent, before they suffer the same fate.
Yonah
One of the more famous of the Trei Asar, Yonah was a son of the widow who Eliyahu stayed with during the famine that rocked the land. When this widow’s son died, it was Eliyahu who brought him back to life. Yonah was a student of Elisha, and was a contemporary of Micha and Ovadiah. The Talmud Yerushalmi (Succah) reports that Yonah received prophecy due to both the merits of being oleh le’regel and his great happiness at the simchas beis hasho’eva. Yonah lived for over 120 years. He was sent to make the people of Ninveh (the capital city of Ashur) repent. According to the Midrash, the king of Ninveh was none other than Pharaoh - formerly the king of Egypt during the Exodus. Pharaoh repented at the last minute whilst drowning at the Yam Suf (he said ‘mi kamocha be’keilim Hashem…’ which we say in Ma’ariv each night), and was saved by Hashem as a result. He later became the king of Ninveh. In fact, Chazal reveal that in order to make Yonah’s job easer, Hashem made Yonah’s face appear like that of Moshe Rabbeinu’s, so that Pharaoh would be moved to repent after remembering the torment suffered at the hands of Moshe.
The Radak asks why the book of Yonah was included in Tanach, given that there is no mention of Bnei Yisrael in it? He answers that the purpose of Sefer Yonah to criticize our stubbornness by contrasting it with Ninveh’s readiness to repent, and to extol Hashem’s chesed and miracles for sustaining Yonah in the fish’s belly and for forgiving one who repents for his sins. The Ran's principle that 'forecasts of impending destruction for other nations act as a warning to Bnei Yisrael' is also relevant here. The Vilna Ga'on has a very deep explanation of the events of Sefer Yonah explaining it as an allegory for the reincarnation of a soul.
Micha
Micha was from the tribe of Yehuda, and learnt Torah from Yeshayahu. His contemporaries were Hoshea, Amos, and Yeshaya; Micha, being the youngest of them, outlived them too. His ‘prophetic career’ began during the times of Uziyah king of Yehuda, and then spanned the reigns of Chizkiyah, Yossam, and Achaz.
Nachum
According to Seder Olam Rabbah (perek 20), Nachum was a prophet in the days of Menashe ben Chizkiya, the king of Yehuda (not so long before the destruction of the first Beis Hamikdash). He was a student of Yoel the prophet, and was a contemporary of Chabakuk. During the days of Nachum, Yehuda was subservient to Ashur and paid taxes to them. Nachum prophesied about the destruction of Ashur and its capital city Ninveh.
Chavakuk
The Zohar writes that Chavakuk was the son of the Shunamis lady who hosted Elisha. In fact, Chavakuk was the son who Elisha promised she would give birth to, and when he died, Elisha brought him back to life. Chavakuk was a prophet in the days of Yehoram ben Achav (just less than 300 years before the destruction of the first Beis Hamikdash). The Seder Olam argues and lists Chavakuk during the times of Menashe ben Chizkiya (some 200 years later), arguing that Chavakuk was a student of Nachum. Indeed, the Abarbanel even cites (but disagrees with) an opinion that Chavakuk lived in the days of Daniel (after the exile and destruction of the first Beis Hamikdash), and that it was Chavakuk who gave food to Daniel in the lion’s den.
Tzefania
Tzefania was a prophet during the times of Yoshiah ben Amon (about 50 years before the destruction of the first Beis Hamikdash, at a time when the ten tribes had already been exiled 200 years earlier). He was a student of Chavakuk and a contemporary of the prophets Yirmiya and Chuldah. Indeed, Chazal say that Tzefania prophesied in the Shuls and Batei Midrash, Yirmiya prophesied in the streets, and Chuldah (one of the seven female prophets) prophesied to the women. Many of Tzefania’s prophecies are about ‘Yom Hashem,’ when Hashem will avenge our serving of idols.
Chaggai
Chaggai was one of the last prophets; he was on the Beis Din of Ezra and was a member of the anshei kenesses hagdolah. Thus, he prophesied during a period after the destruction of the first Beis Hamikdash, when the people were in Bavel. He was a student of either Yechezkel or Baruch ben Neriah, and was a prophet in the days of Daryavesh, king of Persia. According to the Rambam, Chaggai lived until the destruction of the second Beis Hamikdash. Chaggai lived when Bnei Yisrael were in exile, but some had returned to Eretz Yisrael with the permission of Koresh (king of Persia) to build the second Beis Hamikdash. Indeed, Bnei Yisrael had laid the foundation stones for the Beis Hamikdash (and had celebrated accordingly at Sukkos time), until the renegade Bnei Yisrael (Kuthim) convinced Koresh to rescind his permission. Hashem told Chaggai to tell the people that the time had arrived to continue the rebuilding of the Beis Hamikdash (it had now been 70 years since the destruction of the first Beis Hamikdash).
In his Sefer Emes LeYaakov (Bo 12:2), Rav Yaakov Kamenetsky notes that according to the Mishnah in Shekalim (6:1) it would seem that the people knew where the original Aron was during the times of the second Temple - yet they did not retrieve and reinstall it. Similarly, the people kept their Aramaic language despite having returned to Eretz Yisrael to build the second Temple. Why? Rav Yaakov answers that the second Beis Hamikdash was only supposed to be a temporary stage to bring us up to a level whereby we could beckon in the final redemption and the third Temple. Thus, the people placed reminders (they kept their langauge and did not retreive the Aron) to ensure that they did not mistake this period for anything more than a conduit to the ultimate redemption. This is also why they did not appoint a king from Beis David during this era. With this principle, Rav Yaakov explains the oddity in the order of the books of the prophets. Why are the prophecies of Yechezkel (which concern the third Mikdash) put before those of Chagai (which refer to those of the second Mikdash)? For the third Mikdash gave the correct perspective to the second Mikdash.
Zecharia
Zecharia was a contemporary of Chaggai; he lived during the period after the destruction of the first Beis Hamikdash, when Bnei Yisrael were in Galus in Bavel. He was one of the anshei kenesses hagdolah. He was either a student of Yechezkel or Baruch ben Neriah. His prophecies are often cryptic, and Rashi writes that we will not fully understand them until the days of Moshiach.
Malachi
The Gemara (Megillah 15a) reports that some opine that Malachi was Mordechai of the Purim story. Other commentaries say that Malachi was Ezra HaSofer, while others believe Malachi to be a separate individual. Malachi was a contemporary of Chaggai and Zecharia. Malachi moved from Bavel to Eretz Yisrael and was one of the anshei kenesses hagdolah. He was the student of either Yechezkel or Baruch ben Neriah, and he lived at a time when many of Bnei Yisrael were unfamiliar with a lifestyle of Torah and mitzvos. For example, many had married out and the Kohanim did not offer the right sacrifices in the Beis Hamikdash. Malachi is the final book of the Trei Asar and his prophecies center upon fixing the wrongs of the generation who had returned to Eretz Yisrael from Bavel, including intermarriage and desecration of Shabbos.
[1]The Ramban in Shemos writes that the reason the miracle of Yocheved's birth (at old-age) was not recorded was because it was not preceded by a prophecy.