Question: Out of all the people of the ancient world, why did Gd choose Abraham as the ancestor of the ‘chosen people’? And why did he chastise the Israelites through death so often?
Answer: There is one answer to both of your questions. Gd wanted a People who would be able to deliver His pure message to the world. Abraham was the only one of his generation who recognized the foolishness of idolatry and committed himself to monotheism. From time to time, as Israel becomes too influenced by the false messages of the gentile nations around them, Gd purifies them.
All the Best,
Rabbi Azriel Schrieber