Concluding our Advent look at Messianic prophecies for this year, a series which we began in Advent 2011 and continued in 2102 and 2013, the earlier posts of the series may be read here, here, here ,here, here, here, here, here , here , here, here, here, here , here, here, here , here, and here, we come to Isaiah 40: 1-5:
 Be comforted, be comforted, my people, saith your God.
 Speak ye to the heart of Jerusalem, and call to her: for her evil is come to an end, her iniquity is forgiven: she hath received of the hand of the Lord double for all her sins.
 The voice of one crying in the desert: Prepare ye the way of the Lord, make straight in the wilderness the paths of our God.
 Every valley shall be exalted, and every mountain and hill shall be made low, and the crooked shall become straight, and the rough ways plain.
 And the glory of the Lord shall be revealed, and all flesh together shall see, that the mouth of the Lord hath spoken.
As Saint Augustine notes, this is a clear reference to John the Baptist:
Now in those days came John the Baptist, preaching in the wilderness of Judæa, and saying, Repent ye, for the kingdom of heaven is at hand. For this is He that is spoken of by the prophet Isaiah, saying, The voice of one crying in the wilderness, Prepare ye the way of the Lord, make His paths straight. Mark also and Luke agree in presenting this testimony of Isaiah as one referring to John. Luke, indeed, has likewise recorded some other words from the same prophet, which follow those already cited, when he gives his narrative of John the Baptist. The evangelist John, again, mentions that John the Baptist did also personally advance this same testimony of Isaiah regarding himself. And, to a similar effect, Matthew here has given us certain words of John which are unrecorded by the other evangelists. For he speaks of him as
preaching in the wilderness of Judæa, and saying, Repent ye, for the kingdom of heaven is at hand; which words of John have been omitted by the others. In what follows, however, in immediate connection with that passage in Matthew’s Gospel—namely, the sentence,
The voice of one crying in the wilderness, Prepare ye the way of the Lord, make His paths straight,— the position is ambiguous; and it does not clearly appear whether this is something recited by Matthew in his own person, or rather a continuance of the words spoken by John himself, so as to lead us to understand the whole passage to be the reproduction of John’s own utterance, in this way:
Repent ye, for the kingdom of heaven is at hand; for this is He that was spoken of by the prophet Isaiah, and so on. For it ought to create no difficulty against this latter view, that he does not say,
For I am He that was spoken of by the prophet Isaiah, but employs the phraseology,
For this is He that was spoken of. For that, indeed, is a mode of speech which the evangelists Matthew and John are in the habit of using in reference to themselves. Thus Matthew has adopted the phrase,
He found a man sitting at the receipt of custom, instead of
He found me. John, too, says,
This is the disciple which testifies of these things, and wrote these things, and we know that his testimony is true, instead of
I am, etc., or,
My testimony is true. Yea, our Lord Himself very frequently uses the words,
The Son of man, or,
The Son of God, instead of saying,
I. So, again, He tells us that
it behooved Christ to suffer, and to rise from the dead the third day, instead of saying,
It behooved me to suffer. Consequently it is perfectly possible that the clause,
For this is He that was spoken of by the prophet Isaiah, which immediately follows the saying,
Repent ye, for the kingdom of heaven is at hand, may be but a continuation of what John the Baptist said of himself; so that only after these words cited from the speaker himself will Matthew’s own narrative proceed, being thus resumed:
And the same John had his raiment of camel’s hair, and so forth. But if this is the case, then it need not seem wonderful that, when asked what he had to say regarding himself, he should reply, according to the narrative of the evangelist John,
I am the voice of one crying in the wilderness, as he had already spoken in the same terms when enjoining on them the duty of repentance. Accordingly, Matthew goes on to tell us about his attire and his mode of living, and continues his account thus: And the same John had his raiment of camel’s hair, and a leathern girdle about his loins, and his meat was locusts and wild honey. Mark also gives us this same statement almost in so many words. But the other two evangelists omit it.