Hashem is telling Avraham to leave for his own benefit. As long as he remained in Charan, he would not merit the privilege of begetting children or the opportunity of successfully reaching out to a pagan society. Interestingly, Chazal consider Avraham Avinu’s move to be one of the asarah nisyonos, ten trials, to which he was subjected. This seems questionable. Imagine that someone who is r”l childless is told that, by traveling out of the country, he will meet a famous doctor who has successfully treated people who previously had not been blessed with children. Would anyone consider this a trial and resist departing? Moreover, if he is told that his and the doctor’s expenses will be paid for, he would immediately run to see that doctor. In this case, Hashem is telling Avraham to go from here to Eretz Yisrael where he will be blessed with children, honor and prosperity. Yet, Chazal consider it to be a trial! Why is this?
Horav Ovadiah Yosef, Shlita, explains that Avraham was concerned about the inroads he had made in this community and the spiritual loss that would ensue if he were to prematurely leave. It was well-known that he was miraculously saved from the fiery furnace which Nimrod, the evil king, had prepared for him. Indeed, Chazal tell us that Hashem personally saved Avraham. No doubt, such an example of Kiddush Hashem would leave an indelible impression on even the most ardent pagan. Certainly, this miracle provided Avraham Avinu with access to everyone. He succeeded in bringing many people into the fold. Suddenly, the “star” of the show was leaving, going to a new place where nobody had heard of him or of the miracle that he had experienced. What should he do?
Hashem explained to Avraham that one who believes in Him as a result of logical deduction will maintain his conviction – in contrast to the individual who is attracted by miracles. He was to go to Eretz Yisrael in order to teach the people about monotheism. No miracles, no wonders. Just teaching, learning and caring, and he would succeed. We have only to look at contemporary society to see how true this still is today. Those who have “returned” as a result of artificial inspiration or exposure to miracles do not necessarily remain for the duration of the “trip.” Those whose belief is founded in sagacious rationalization of the facts, coupled with emunah, true belief, maintain their conviction, regardless of the challenges they might encounter.