Elias truly shall first come ( ἐ ìρχεται, cometh). Many of the best manuscripts and editions omit "first." The Vulgate has merely, Elias quidem venturus est. It is probably inserted in our text from the parallel passage in Mark, where it is certainly genuine.
Christ is here alluding to his own second coming, which shall be preceded by the appearance of Elijah in person. This seems to be the plain meaning of the prophecy in Malachi, and of Christ's announcement, and is confirmed by St.
John's statement concerning the two witnesses (Revelation 11:3, Revelation 11:6). That the paragraph cannot refer to John the Baptist is plain from the tenses used in this verse contrasted with those in the following.
To regard verse 12 as simply a correction of verse 10 is to do violence to language, and to leave one half of Malachi's prediction unexplained. Restore ( ἀποκαταση ìσει) all things. The event is still future, and was not fulfilled in the Baptist's preaching, however deep and extensive may have been its influence.
Of course, John in a partial degree reproduced the character and acts of Elijah, directing the people to the eternal principles of justice and righteousness, to a reformation of religion and morals; but he could not be said to have reconstituted, re-established all things; though it is possible that, had his message been received and acted upon, some such effects would have been produced.
How and in what degree Elijah, again appearing and living on earth, will effect this great achievement, we know not. We can only fall back on the ancient prophecy, which affirms that "he shall turn the heart of the fathers to [or, 'with'] the children, and the heart of the children to [or, 'and'] their fathers" (Malachi 4:6), and expect that in some way, known unto God, he shall convert one and all, young and old, unto the Lord; or unite the Jews who are the fathers in the faith to Christians who are their children, and thus embrace Jew and Gentile in one fold under one Shepherd.