Summary: Though none can see it, God is working behind the scenes and through the course of history to prepare the way for the coming of the Messiah, setting the earthly stage for the entry of His only begotten Son into the world.
Preparing the Way
Isaiah 40:3-5, 9-11
When God called the Jewish people, he gave them everything necessary to follow Him and for salvation, principally, the Law. When they entered the Holy Land, God warned the Jewish people not to intermarry with the Gentile and to always keep God first. They did for awhile but as the generations passed, the Jews were continually tempted by the Gentiles and their gods around them. Perhaps a key decision indicating the direction of the Jews away frok god was when in the face of the looming threats all around them, they cried out for a king when God was already their king. So God sent judges but judges were not enough. Then God sent the prophets to call people back to Him but their warnings went unheaded. Even when Josiah recalled the people to God and rededicated the nation and people to God, it was shortlived. Finally their rebellion was too much and God realized there had to be another way.
http://paradigm-shift-21st-century.nl/plaatjes/captivity-of-judah-in-babylon.jpg When Nebuchadnezzar defeated Jerusalem in 597 BC, he deported more than 10,000 Jews to the city of Babylon, the capital of the Chaldean Empire in what is now modern day Iraq. They took the most prominent, educated and skilled citizens of Judah. The deported Jews formed their own community in Babylon and retained their religion, and practices. They were allowed to farm and perform other sorts of labor to make a living. They married, built homes, had children and settled in because Jeremiah told them they would be there for 70 years. Despite all of this, exile was difficult as they now found themselves separated from home, Temple, land and God because God was viewed as tied to the Holy Land. The Hebrew faith was built on the promise that God would protect the Hebrews and use them for His purposes in human history. Questions of why and how God could allow this to happen and whether God had abandoned them were prevalent. They were forced to question their understanding of and relationship to God and what it means to be a faithful and obedient Jew. Perhaps the most difficult and painful lesson they learned in exile is that it was their own rebellion which brought the judgment of God upon them, as the prophets had continually warned. As the years rolled by, a spirit of despair and hopelessness fell upon them.
After several decades, a follower of Isaiah rose up to speak a message of hope to the exiles: their punishment is almost done and God is now preparing the way for them to return home. He will go before them, making a straight, smooth and level path home; in other words, a much easier journey home than their journey here. They ended up returning in three waves one under Zerubbabel in 535 B.C., Ezra in 458 B.C., and Nehemiah in 444 B.C. They rebuilt Jerusalem, its Temple, its walls, their homes and their lives. There was a renewed commitment to the faith, the study of the Scriptures and leading holy lives, separated from the influence of the Gentiles. But after a generation or two, they wandered from the path again.