The Hebrew word can refer to both a heavenly “angel” or an earthly “messenger.” It is correctly translated “messenger,” and refers to a person. The title in Hebrew (“my messenger”) is also the name of the author of this prophetic book (Malachi). It is possible that the messenger that the Lord would send refers to Malachi. But in light of the reference to Elijah in Malachi 4:5, and the Lord Jesus’ explanation in Matthew 11:10–14, this messenger (Elijah) is the forerunner of Jesus Christ, namely, John the Baptist.
1 “Behold, I send my messenger, and he will prepare the way before me. And the Lord whom you seek will suddenly come to his temple; and the messenger of the covenant in whom you delight, behold, he is coming, says the LORD of hosts.