In verse 1, God is speaking as we can see from the last phrase ‘says the Lord of hosts’. Yet he also describes the coming One as the Lord, which means that in this verse we have one divine person speaking about another divine person. Since the one that is to come is Jesus, the Son, it is likely that the speaker in verse 1 is the Father.
Not only is Jesus divine, he is also called ‘the messenger of the covenant’. The term ‘messenger’ means delegate or representative. When Jesus arrives, he is going to teach Israel about the covenant, which is a reference to the way that God deals with sinners.
The Saviour, when he came, gave instructions about the covenant ways of God. As far as the people in general were concerned, he pointed out to them how they had failed to keep their covenant commitments, how they had broken God’s law. Yet he also referred often to the promises made to Abraham; for example, when the centurion revealed that he had faith, Jesus spoke about the great number that would come from the east and west and sit down with Abraham, Isaac and Jacob, which was a reference to the covenant God made with Abraham. Further, he spoke with his disciples in the upper room about the fulfilment of the new covenant prophesied by Jeremiah in which the inner heart of his people would be changed.
The teaching of the divine Messenger was clearly different from that of the previous prophets. One obvious difference was the fullness with which Jesus taught. Not only was the teaching of Jesus fuller than the messages of the prophets, it was also different in that he was the subject of his own teaching. They spoke about him, he spoke of himself.
Malachi states that the Messenger will come to his temple. Twice Jesus came to the temple in Jerusalem and discovered inappropriate practices taking place. On each occasion he cleared the temple of those who sold animals and other products and overthrow the tables of the moneychangers. The situations he found indicate that nothing had improved since the days of Malachi four hundred years previously.