Or otherwise, we must understand, that although these words are not found in Isaiah, still the sense of them is found in many other places, and most clearly in this which he has subjoined, “The voice of one crying in the wilderness.” For that which Malachi has called, the angel to be sent before the face of the Lord, to prepare His way, is the same thing as Isaiah has said is to be heard, “the voice of one crying in the wilderness, saying, Prepare ye the way of the Lord.”
But in each sentence alike, the way of the Lord to be prepared is proclaimed. It may be, too, that Isaiah occurred to the mind of Mark, in writing his Gospel, instead of Malachi, as often happens; which he would, however, without doubt correct, at least when reminded by other persons, who might read his work whilst he was yet in the flesh; unless he though that, since his memory was then ruled by the Holy Spirit, it was not without a purpose that the name of one prophet had occurred to him instead of another. For thus whatsoever things the Holy Spirit spoke by the prophets are implied each to have belonged to all, and all to each.
Reproduced in full. Translation: Oxford 1841 (Newman), public domain (Public domain).