Great Sermon! WHY DID GOD PUNISH ISRAEL SO SEVERELY?
Israel always sinned against God because of unbelief. The Old Testament is a chronicle of Israel's repeated failure to obey God and its refusal to keep His commandments.
Because Israel rejected Jesus, no Israeli has a right to occupy their land on the basis of a covenant. Jesus had warned, "Therefore say I unto you, The kingdom of God shall be taken from you, and given to a nation bringing forth the fruit thereof". (Mat 21:43 kjv).
In 135 A.D. the Romans reduced Jerusalem to a pile of rubble. The entire population of Israel was permanently evicted from Palestine. Jesus Christs' fateful words, "Behold, your house is left unto you desolate." (Mat 23:38 kjv), met a complete fulfilment.
This did not mean God rejected Israel from any hope of salvation, but it did mean that Judaism was no longer the divinely appointed means of approaching God. Israel was broken off because of unbelief of Jesus as their Messiah and that is the reason why God punish Israel so severely from thereon through Holocaust and even until now.