One hundred years after exile, the Israelites who had returned to Jerusalem were as evil and corrupt as their ancestors. The book of Malachi addresses their sins—they’ve corrupted the sacrificial system, hoarded their money, and worshiped foreign gods. But despite all of this, God does not forget his promises to deliver his people and establish a new Jerusalem.
The book of Malachi sums up what the whole Hebrew Bible has been pointing to—God’s people cannot be faithful to the covenant. They’ve failed again and again. And while God will deal with their sin, he will not abandon them. He promises to redeem a remnant and send a Messiah to fulfill his covenant promises.