Since when has Satan been trying to destroy the nation of Israel?
Satan began his effort to destroy the nation of Israel as soon as God made the covenant with Abraham. That process has continued for over 4,000 years, because God promised to fulfill everything through that nation, and destroying the Jew would thwart His plan for the ages.
Les explains that the running battle between Satan and Jesus Christ began when God told Satan He would put enmity between Satan's seed and the woman's seed, which Galatians identifies as Christ. From that moment on, whenever Satan understands God's particular program, he comes in to disrupt it. So just as soon as God made the covenant with Abraham, Satan began a process that has been running for over 4,000 years to destroy the nation of Israel. Because God promised that everything would be fulfilled through that little nation, if Satan could destroy the Jew, he would thwart God's plan for the ages. This running battle begins there and continues.