What is the meaning of Matthew 3:3?

Mt ch 3Mt 3:1Mt 3:2Mt 3:3Mt 3:4Mt 3:5Mt 3:6Mt 3:7Mt 3:8
Mt 3:9Mt 3:10Mt 3:11Mt 3:12Mt 3:13Mt 3:14Mt 3:15Mt 3:16Mt 3:17

Reference

For this is he that was spoken of by the prophet Esaias, saying, The voice of one crying in the wilderness, Prepare ye the way of the Lord, make his paths straight. (Matthew 3:3 KJV)

For this is he that was spoken of through Isaiah the prophet, saying, The voice of one crying in the wilderness, Make ye ready the way of the Lord, Make his paths straight. (Matthew 3:3 ASV)

For this is he who has been spoken of through Esaias the prophet, saying, Voice of him that crieth in the wilderness: prepare ye the way of [the] Lord, make straight his paths. (Matthew 3:3 DBY)

For this is he who was spoken of by Isaiah the prophet, saying, “The voice of one crying in the wilderness, make ready the way of the Lord. Make his paths straight.” (Matthew 3:3 WEB)

for this is he who was spoken of by Isaiah the prophet, saying, ‘A voice of one crying in the wilderness, Prepare ye the way of the Lord, straight make ye His paths.'(Matthew 3:3 YLT)

Interlinear

Mt 3:3 For /gar/ this /houtos/ is he /esti/ that was spoken /rheo/ of by /hupo/ the prophet /prophetes/ Esaias, /Hesaias/ saying, /lego/ The voice /phone/ of one crying /boao/ in /en/ the wilderness, /eremos/ Prepare ye /hetoimazo/ the way /hodos/ of the Lord, /kurios/ make /poieo/ his /autos/ paths /tribos/ straight. /euthus/

Albert Barnes’ Commentary

Verse 3.  The prophet Esaias.  The prophet Isaiah.  Esias is the Greek mode of writing the name.  This passage is taken from Isa 40:3. It is here said to have been spoken in reference to John, the forerunner of Christ.  The language is such as was familiar to the Jews, and such as they would understand.  It was spoken at first with reference to the return from the captivity at Babylon.  Anciently, it was customary in the march of armies to send messengers, or pioneers, before them, to proclaim their approach; to provide for them; to remove obstructions; to make roads, level hills, fill up valleys, etc.  Isaiah, describing the return from Babylon, uses language taken from that custom. A crier, or herald is introduced.  In the vast deserts that lay between Babylon and Judea, he is represented as lifting up his voice, and, with authority, commanding a public road to be made for the return of the captive Jews, with the Lord as their deliverer. “Prepare ye the way of the Lord, make his paths straight,” says he; or, as Isaiah adds, Let the valleys be exalted, or filled up, and the hills be levelled, and a straight, level highway be prepared, that they may march with ease and safety. See Barnes for Isa 40:3. 

As applied to John, it means, that he was sent to remove obstructions, and to prepare the people for the coming of the Messiah; like a herald going before an army on the march, to make preparations for their coming. 

{m} “by the prophet Esais” Isa 40:3