Malachi is the last book of the Old Testament and belongs to the period of Nehemiah. The prophets message is to the priests and the people, charging them with indifference, doubt, and immorality. Malachi tells of the coming day of the Lord and closes the book with a prophecy of John the Baptist.

Malachi 2

2:4 And ye shall know that I have sent this commandment unto you, that my covenant might be with Levi, saith the LORD of hosts.