When John was conceived, or rather, when he was born, the Holy Spirit prophesied concerning this man: "He will be the Forerunner of the Most High, in the spirit and power of Elijah" (Lk 1:17).
Therefore he was not Elijah, but was in the spirit and power of Elijah. What does this mean, "in the spirit and power of Elijah"? It means in the same Holy Spirit, in the order of Elijah.
Why in the order of Elijah? Because what Elijah will be for the second coming, John was for the first coming.
"And they said to him, 'What then? Are you Elijah?'" (Jn 1:21). He answered, "I am not Elijah." Since Christ was to send Elijah before Himself, John said, "I am not Elijah," and he gave rise to a doubt in us.
Care must be taken lest those who understand this insufficiently suppose that John spoke against what Christ said. In the same place where the Lord Jesus Christ spoke something about Himself in the Gospel, the disciples asked Him: "Why then do the scribes, that is, the experts in the Law, say that Elijah must come first?"
And the Lord said to them: "Elijah has already come, and they did to him whatever they wished; and if you wish to know, he is John the Baptist" (cf. Mt 17:10-13).
The Lord Jesus Christ said: "Elijah has already come; he is John the Baptist." But John, answering the question, acknowledged that he was not Elijah, just as he acknowledged that he was not the Christ.
In any case, he truly acknowledged that he was not the Christ, just as he truly acknowledged that he was not Elijah.
How, then, shall we compare what was said by the herald with what was said by the Judge? It is inadmissible that the herald should lie, for he pronounces what he hears from the Judge.
Why then does he say, "I am not Elijah," while the Lord says, "He is Elijah" (Mt 11:14)? Because the Lord Jesus Christ wished His coming advent to be revealed in him as a type. He wished to say that John was in the spirit of Elijah.
What John was at the first coming, Elijah will be at the second coming. As there must be two comings of the Judge, so there must be two heralds. Yet the Judge is Himself one, and the heralds are two, but there are not two judges.
For the Judge first had to come to be judged. He sent a herald before Himself and called him Elijah, because what Elijah is to be at the second coming, John became at the first.
Indeed, beloved, see how truly I speak. When John was conceived, or rather, when he was born, the Holy Spirit prophesied what was to be fulfilled in this man: "He will be the Forerunner of the Most High, in the spirit and power of Elijah" (cf. Lk 1:17).
Thus he is "not Elijah," but in the spirit and power of Elijah. What does "in the spirit and power of Elijah" mean? It means in the same Holy Spirit, under the form of Elijah.
Why under the form of Elijah? Because what Elijah will be at the second coming, John was at the first.
Therefore John, speaking in the literal sense, gave a correct answer. But the Lord spoke figuratively: "Elijah is John." The other, as I have already said, spoke literally: "I am not Elijah."
If you have in mind the figure of the Forerunner, John is Elijah. For at the first coming he was what Elijah will be at the second. But if you ask about the concrete person, John is John, and Elijah is Elijah.
Therefore the Lord rightly said, in the sense of the type: "He is Elijah." And John rightly said, in the sense of the concrete person: "I am not Elijah." Neither John lied nor the Lord. Neither the herald lied nor the Judge, if you understand this.
And who can understand it? The one who imitates the humility of the herald and grasps the majesty of the Judge. For there is no one more humble than the herald himself.
My brethren, John had no greater merit than this humility. Though he could have lied to men, so that they would think him the Christ and receive him as the Christ, he openly confessed and said: "I am not the Christ."
Such grace rested upon him, and so excellent was he. Yet he confessed openly.
"What then? Are you Elijah?" (cf. Jn 1:20-21). If he had said, "I am Elijah," it would have meant that Christ had already come in His second coming to judge, and had not come in the first to be judged.
He said, "I am not Elijah," as if saying thereby that Elijah is still to come. Behold, then, the humble Christ, before whom John came, and not Christ filled with majesty, before whom Elijah will come.
For the Lord also proclaimed this thus: "He is John the Baptist, who is yet to come."
He came in the form of a type, while in his own person Elijah is still to come. Then Elijah in person will be Elijah; now, according to likeness, he was John.
The two heralds gave their likenesses to each other and preserved their persons. Yet there is one Lord, the Judge, with this or that herald going before Him.