Malachi is the final book of the Old Testament and, upon its completion, there was no further divine Word until four hundred years had passed and the voice of John the Baptist was heard. It is unique because, as one writer said, "Of the fifty-five verses in this book, forty-seven are spoken by God - the highest portion of all the prophets."
Malachi's name means God's messenger. He was one of the rare voices who faithfully proclaimed the Word of Lord. We know precious little about this man except that he was a contemporary of Nehemiah and prophesied after Haggai and Zechariah. Malachi ministered at a time after the temple had been completed, the sacrifices had resumed and the ceremonial proceedings, as far as their outward performance was concerned, had been restored. There was much about the conditions of Malachi's times to parallel our own. Many people were religious, but their religion was a shallow, heartless thing. It was a pasted-on veneer, impressive to men but despised by God who sees through the hypocrisy. "Having a form of godliness, but denying the power thereof" (2 Timothy 3:5). These were the circumstances that existed when God sent to these people a prophet.
One of the unusual things about this book is that over and over again questions are asked by the Lord as a means of exposing the guilt of Judah. These were intended to fill the hearts of the people with shame and prepare them for the gospel announcement that "the Messenger of the covenant" of grace would "suddenly appear...behold, He shall come" (3:1). Malachi declares the certainty of the Incarnation of Christ Who would save His people from their sins by His righteous obedience to God. In spite of man's wickedness, the Lord will always be faithful to His covenant promises (3:6). Finally, the prophet foretells the second coming of our Savior. When "the Sun of Righteousness" shall appear (4:2) and gather His jewels into His everlasting kingdom (3:17), He will divide the sheep from the goats. In that day He will make known to all the world those that are righteous, who will be saved eternally, and those that are wicked, who will perish forever (3:18).