For the phrases “A voice cries out: ‘In the wilderness prepare the way of the Lord, make straight in the desert a highway for our God. Every valley shall be lifted up, and every mountain and hill be made low; the uneven ground shall become level, and the rough places a plain. Then the glory of the Lord shall be revealed, and all people shall see it together.'” see Luke 3:4ff.
Note that this quote in the New Testament is not taken from the Hebrew Bible but from the Greek Septuagint (LXX) which translates to English as “A voice of one crying out in the wilderness: ‘Prepare the way of the Lord; make straight the paths of our God. Every ravine shall be filled up, and every mountain and hill be made low, and all the crooked ways shall become straight and the rough place shall become plains. Then the glory of the Lord shall appear, and all flesh shall see the salvation of God.'” (Translation by NETS — for the Greek version see the title’s tooltip)