Originally from here.

We referred in our previous meditation to the link between Elijah and John the Baptist. At the end of the Book of Malachi, in the last few verses of his prophecies, it is foretold that, before the great and terrible day of the Lord, Elijah would be sent. When you open the New Testament you find the disciples referring to that prophecy and asking the Lord Jesus about it, seeing that He claimed to be the Messenger of the Covenant, the Lord Who had come. With that in mind, they were in reality voicing their own perplexity: The prophets said Elijah would come first, but we have not yet seen Elijah! The Lord Jesus pointed them to John the Baptist and said that this was Elijah, that Elijah had come and they had done to him what they would. When you go back to the prophecies concerning John the Baptist, you find this among the things foretold: “And he shall go before His face in the spirit and power of Elijah…” (Luke 1:17). In thinking upon that second chapter of the Gospel by Luke, in which occurs the account of the birth of the Lord Jesus, and the birth of John the Baptist, you can hardly fail to be impressed with the way these two are brought together in the chapter. It is a most remarkable thing. We are shown Zacharias fulfilling his course in the temple, the angel appearing to him, and all that the angel spake as to the birth of John. Then there is a breaking off, and the record of the angel appearing to Mary is given, and the annunciation. This is followed by the visit of Mary to her cousin Elizabeth in the hill country, and the two coming together in that way. It was said that John the Baptist should go before the face of the Lord, and that he would do so in the power and spirit of Elijah. You look for the inner meaning and significance of this, and you remember Elijah and what he stood for. Elijah is an abiding example of a consuming jealousy for the rights of God. Now that spirit is transferred to John the Baptist, and he runs before, clears the way, announces the coming of Christ in the spirit of Elijah. He is bringing in the rights of God in the Person of Jesus Christ. He is, in effect, in purpose, bringing God into His place in the Person of His Son. John the Baptist closes the great succession of the prophets (he is the greatest of the prophets in one sense) by handing the Lord Jesus into the place of God’s full rights, and pointing to Him, and saying to all who beheld, “Behold, the Lamb of God…” That was to say, in effect, This is the One in Whom God secures His rights; here is God coming into His place. Are you prepared for Him to rule in your life? That was the issue from that time onward.

That is the zeal of the Lord, and that is the way—as becomes instantly patent—to heavenly fulness. When we speak of heavenly fulness we cannot dissociate it from the Lord Jesus. In Him all the fulness dwells, but the question is, How are we coming into that fulness which is in Christ, and of which we saw the life of Elisha to be typical? It is by the Elijah way; by that way wherein God has His full place and all His rights secured to Him. You can see this throughout Elijah’s life.

Again, passing in review some of the salient points of his life, you see that his jealousy for the Lord marked every step of the way. The introduction of Elijah is very sudden and abrupt. You are simply told that Elijah the Tishbite confronted Ahab one day and said: “As the Lord, the God of Israel, liveth, before Whom I stand, there shall not be dew nor rain these years, but according to my word.” Thus suddenly, coming from we know not where, appearing on the scene and making his declaration, we meet for the first time this man who stands for the rights of God.