John Calvin Commentary John 1:23

"He said, I am the voice of one crying in the wilderness, Make straight the way of the Lord, as said Isaiah the prophet." — John 1:23 (ASV)

The voice of him who crieth. Since he would have been accused of rashness for taking on the office of teaching if he had not received a commission, he shows the duty he had to perform and proves it with a quotation from the Prophet Isaiah 60:3. Therefore, it follows that he does only what God commanded him to do. Isaiah does not, indeed, speak there of John alone; but, promising the restoration of the Church, he predicts that joyful voices will still be heard, commanding to prepare the way for the Lord. Although he points to the coming of God when He brought the people back from their captivity in Babylon, yet the true fulfillment was the manifestation of Christ in the flesh. Among the heralds who announced that the Lord was near, John held the chief place.

To enter into clever inquiries, as some have done, into the meaning of the word Voice, would be frivolous. John is called a Voice because he was commanded to cry. It is undoubtedly in a figurative sense that Isaiah gives the name 'wilderness' to the miserable desolation of the Church, which seemed to prevent the people's return; it is as if he had said that a passage would indeed be opened for the captive people, but that the Lord would find a road through regions where there was no road.

But that visible wilderness, where John preached, was a figure or image of the terrible desolation that took away all hope of deliverance. If this comparison is considered, it will be easily seen that the prophet's words have not been distorted in this application of them. For God arranged everything in such a way as to place before the eyes of His people, who were overwhelmed by their calamities, a mirror of this prediction.