The name Malachi refers to a messenger; the Book of Malachi is titled "ykalm" in Hebrew, which means "Messenger of Yahweh" or "My Messenger." Malachi likely lived between 568 and 433 B.C. Nothing is known about Malachi's life except for his prophecies, which appear in the Book of Malachi. The Book of Malachi reminds people that Yahweh tries to help them, and that he honors their faithfulness and holds them accountable for their wrongdoings.
Malachi may not even be the prophet's real name. Some Bible scholars believe that Malachi is the book's name, rather than the author's. The Book of Malachi contains seven rhetorical questions that are designed to make the people of Israel return to God. The people ask Malachi how God has loved them, and Malachi explains how God chose Israel. Malachi goes on to explain how the people have sinned and that God is not accepting their offerings because they have been marrying foreign women.
Other issues that the book covers include God bringing justice to wicked people, a return to Israel, tithing, and God's assurance that people who live faithfully are rewarded in the future. The Book of Malachi ends with a plea to live according to Moses' law, and a promise that God is to send the prophet Elijah to announce the Day of the Lord. The book ends with a threat, wherein God says that he plans to curse the land if the Israelites reject Elijah.