Luke 3:5

Every valley, &c. The metaphor is derived from pioneers who go before the march of a king. There is a remarkable parallel in Josephus (B. J.iii. 6, § 2), where he is describing the march of Vespasian, and says that among his vanguard were "such as 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 (comp. prokoptein= -to advance" in Luke 2:52), that the army might not be tired." The Jews fabled that the Pillar of Cloud and Fire in the desert smoothed the mountains and filled the valleys before them. Tanchuma, f. 70, 3 on Numbers 20:22.

Every valley shall be filled, &c. i. e. the humble and meek shall be exalted, and the mighty put down. Compare Isaiah 2:12-15, "The day of the Lord of hosts shall be upon every one that is proud and lofty, and upon every one that is lifted up, and he shall be brought low.… And upon all the high mountains, &c." Zechariah 4:7, "Who art thou, O great mountain? Before Zerubbabel thou shalt become a plain."

the crooked shall be made straight The words in the original recall the names Jacoband Jeshurun; as though it were "then the Supplanter shall be turned into Prince with God" or "the beloved" (Isaiah 44:2; Isaiah 11:4). The general meaning of the prophecy is that no obstacles, whether they arose from depression, or power, or pride, or cunning perversity, or menacing difficulties, should be able to resist the labours of the Pioneers and Heralds of the Kingdom of God. The feeble instrumentality of Galilaeans should be strengthened; the power of the Romans and Herods should be shattered; the duplicity and plots of Pharisees and worldlings should be defeated; the apparently insuperable opposition of Judaism and Heathenism be swept away.