Malachi
Malachi closes the Old Testament with a courtroom conversation. God makes a claim, I have loved you, and the people answer with weary skepticism: How have you loved us? Six such disputes expose a community gone gray in its faith: priests offering blind animals, husbands abandoning the wives of their youth, tithes withheld, and everyone muttering that serving God is pointless. Through it all God pleads and warns: he does not change, he keeps a book of remembrance for those who fear him, and his messenger will come to prepare the way. The final promise is a sunrise, righteousness with healing in its wings.
Malachi, meaning "my messenger"; possibly a name or a title.
Around 460–430 BC, after the temple's rebuilding.
Post-exilic Judah, spiritually listless a century after the return.
To confront half-hearted worship and covenant unfaithfulness, calling Judah back to God before the coming day.