I would add a little by way of postscript.
The John the Baptist of the gospels is identified (officially, not personally) with the Elijah of Malachi. (See Matt. 11; Mark 1; Luke 1; Luke 7.) John the Baptist stood ready to fulfill the promise of the prophet to Israel. He was, as the messenger that went before the face of the Lord of the temple; and as the one who would turn the hearts of the fathers to the children, and the hearts of the children to the fathers. But Israel was unbelieving; and, as the ancient oracle is a standing oracle in the story of that people—“If ye will not believe, surely ye shall not be established,” (Isa. 7:9), Israel remained unblessed.
Elijah, in Ahab’s day, was a restorer, as we see in 1 Kings 18. But this was but for a season. His light was rejoiced in by the people, but Jezebel forced him out into the wilderness again. So with the Baptist. His light was rejoiced in also. But, again, this was only for a season. The multitude were baptized of him; but the wicked hated him; and there was another Jezebel in that day that had him beheaded; and Israel was left unestablished, whether by Elijah or the Baptist.
But the promised Elijah will still appear and lead on to the throne and power of Messiah. For God is true, though every man be a liar. His gifts and calling are without repentance. He will be faithful to Israel, though, as we have seen, Israel under every trial has been unfaithful to Him. He will accomplish His purposes in grace, be the world, be Israel, or man, never so angry or never so perverted. “God is unchangeable both in righteousness and grace.”
“All Israel shall be saved; as it is written, there shall come out of Zion the Deliverer, and shall turn away ungodliness from Jacob” (Rom. 11:26).
Behold the mountain of the Lord
In latter days shall rise,
On mountain-tops above the hills,
And draw the wond’ring eyes.