What did Satan begin doing after God made the covenant with Abraham?
After God made the covenant with Abraham, Satan began a process that has continued for over 4,000 years: destroying the nation of Israel. He targeted Israel because God promised everything would be fulfilled through that nation; if Satan could destroy the Jew, he would thwart God's plan for the ages.
Les explains that once Satan understands God's particular program, he comes in and tries to disrupt it. Just as soon as God made the covenant with Abraham, Satan began a process that has been running for over 4,000 years, aimed at destroying the nation of Israel. God had promised that everything would be fulfilled through that little nation, so if Satan could destroy the Jew, he would thwart God's plan for the ages. This fits the running battle promised earlier: enmity between Satan and the woman, and between Satan's seed and her seed, which Galatians tells us is Christ.