Why the Israelites were into exile?

Answer:  The quick answer is “themselves.”  In Leviticus 26:1-16, God provided the Jews a preview of the blessings they would enjoy if they were faithful to Him and the Law.  Leviticus 26:14-44 likewise provided a preview of what would happen if God removed his favor from them due to disobedience.  God provided them with many blessings but they were unfaithful. The first wave of exiles occurred as a chastisement when the 10 tribe Kingdom of Israel (they had split away from the combined 12 tribe kingdom) strayed greatly from the Levitical Law and was conquered by the Assyrians and dispersed into many nations.  Then Judah (and Benjamin) went down the same evil path.  God had promised seven times (7 times 360 years of blessings or 2520 years) of blessings if they remained faithful to him.  However, in 607 BC (others say 587 BC), their prolonged lack of faithfulness resulted in a severe chastisement when Judah was conquered by Babylon and Jerusalem destroyed.  This started a time period of seven times of Gentile influence and control over the Jewish people which lasted 2520 years until 1914, when the “times of the Gentiles be fulfilled” (Luke 21:24).  The Jews lost all favor in 33 AD when Jesus declared their house was “left desolate” (Matt. 23:37-39).  We know that approximately 40 years later, the Jewish nation was completely destroyed by the Romans and they were dispersed throughout the world as slaves and exiles as Jesus said would happen.  In Leviticus 26:45, however, God reveals he will have mercy on the Jews and remember their covenant with them. We see that 1845 years after they were left desolate, God began to restore them in the land of promise in 1878 AD when the Jews were first allowed to return to Palestine, purchase land, and establish the first community Petah Tikva (Gate of Hope).  Then, 70 years later, as if to correspondingly undo the 70 years of desolation at the hands of Babylon at the beginning of the 2520 years, the Jewish nation of Israel was re-established in 1948.