Luke 3:4

As it is written in the book of the words of Isaiah the prophet, The voice of one crying in the wilderness, Make ye ready the way of the Lord, Make his paths straight. Every valley shall be filled, And every mountain and hill shall be brought low; And the crooked shall become straight, And the rough ways smooth: And all flesh shall see the salvation of God.

This great prophecy is from Isaiah 40:3ff, the same being God's promise of a mighty prophet who would precede the coming of the Messiah, the imagery being that of a herald going before an ancient king to make his journey easier. Josephus relates how Vespasian marched into Galilee, with his men going before him to prepare the way, thus:

(They) were to make the road even and straight and if it were anywhere rough and hard to be passed over, to plane it, and to cut down the woods that hindered their march, etc.[11]

Of course, it was no such thing that John the Baptist would do for Christ. The preparation needed for the rising of the Sun of righteousness was a moral improvement of the people. The conceit that physical descent from Abraham would entitle them to Messiah's blessing, the foolish notion that the Messiah would be a secular king like Solomon, the conviction that he would drive out the Romans and execute a vindictive and punitive judgment against their Gentile enemies, and the widespread hypocrisy and immorality of the people, the selfishness and hardheartedness of the rich, and the greedy gouging of the people by the concessioners in the temple itself, the gross ritualism and secularism that had buried God's true law under the priestly traditions - all these cried out to God for correction; and thus it was no small task that challenged the son of Zacharias!

All flesh shall see the salvation of God ... Isaiah's great prophecy should have alerted the Jews to the inclusion in God's plans of salvation for the Gentiles; but the leaders of the people were set adamantly against any such idea. The chosen people were destined to find in this concept the impossibility of their accepting Christ, which resulted in their own rejection and judicial hardening.