Sefer Chaggai (Haggai) is the book of the prophecies of Chaggai the navi (prophet), one of the books of the Neviim Acharonim (the Later Prophets). It is one of the Trei Asar (the Twelve), the twelve short books of the Neviim that, the Gemara says (Bava Batra 14b), are written together as one sefer.
Chaggai speaks to the people who have come back to Yerushalayim (Jerusalem) from the exile in Bavel (Babylon), when the second Beit HaMikdash (the Jewish Holy Temple) is to be built. All four of his prophecies are dated to the second year of King Daryavesh (Darius), in the sixth, seventh and ninth months. He speaks to Zerubavel ben Shealtiel, the pechah (governor) of Yehudah (Judah), to Yehoshua (Joshua) ben Yehotzadak, the kohen gadol (high priest), and to the she'erit (remnant) of the people.
Chaggai rebukes the people for saying that the time has not come to build the house of Hashem, while they live in finished houses of their own. Their harvests are poor and their wages vanish because Hashem's house lies in ruins. The leaders and the people listen, and twenty-three days later they begin the work.
Hashem encourages those who remember the first Beit HaMikdash and think the new one is nothing. He is with them, and the glory of this later house will be greater than that of the first. Through a question to the kohanim (priests) about holiness and tumah (ritual impurity), Chaggai teaches that the people's offerings have been tamei (impure), and Hashem promises to bless them from the day the foundation is laid. The sefer ends with Hashem's promise to Zerubavel, whom He has chosen and will make like a signet ring.
Sefer Chaggai has two perakim.