Malachi was the last Old Testament book, written about 400 years before Christ. It is a message to the priesthood and nation living in the rebuilt Jerusalem and offering at the rebuilt temple. It touches on the sins and hypocrisy of the priests and people. Some of these are offering blemished lambs, incomplete tithes, and some divorce the wife of their youth.
Malachi reveals God as a refiner of silver, and prophesies of John’s coming to prepare the Lord’s way and of the Lord coming as the messenger of God’s covenant. He is the sun of righteousness who has healing in His wings.