Abraham?s reactions to these two promises differed from each other. When he heard the promise of a son, he reacted with complete faith, as the Torah says, ?And he believed in the Lord, and He accounted it to him as righteousness.? Abraham?s faith was so pure that God considered it ?righteousness? ? faith that went beyond what was necessary. But if we expected him to react to the second promise with such impressive faith, we would be disappointed. When God promises him the Land of Israel, Abraham responds with the question:
“O Lord God, how will I know that I will inherit it?”
(Breishit 15, 8)
Abraham requests a sign, some symbol that will strengthen his faith that the promise of his future descendants inheriting the Land of Israel will be fulfilled. This is contrary to the previous promise of a son which Abraham believed whole heartedly. The complication increases when we discern the realistic gap between both promises. The promise of a son entailed a manifest miracle since both Abraham and Sarah were elderly, whereas the promise of the Land would not entail a manifest miracle. It is the way of the world that nations conquer lands from one another and this promise should not have caused Abraham to be skeptical.
This difference in Abraham?s faith in the two promises aroused questions among many commentators. Some separated the promises, claiming they occurred at different periods of Abraham?s life. We will try to comprehend why he reacted this way, assuming that both promises were made one after the other at the same event as is implied in the text, and that despite this Abraham reacted so differently to each of them.
When we analyze the two promises Abraham received we discover conspicuous differences. One difference is that the promise of a son was slated to be fulfilled with Abraham and Sarah themselves, while the promise of the land was slated to be fulfilled with their descendants, generations into the future. Another difference is that the promise of a son did not require the participation of Abraham or Sarah, whereas the promise of the Land required the Jewish nation to be active and conquer it.
When God promises Abraham a son, he has no doubt that this promise will be fulfilled since God is able to do anything He chooses and can bequeath children even to those for whom nature does not make it possible. But when God promises the Land of Israel to Abraham, he knows this promise is dependent on his descendants. He asks himself: Will they be worthy of this? Will they know to act as they are expected to? Abraham cannot answer and so he asks for a sign. How can he be sure his descendants will conquer the Land? The promise being fulfilled rests on their actions. God does not do what man has to do and the fulfillment of this promise is dependent on the actions of man, not just of God.
Indeed, Jewish faith leaves space for man. It does not take the place of man. When man is called to action, he cannot depend on God to act in his stead. Abraham, aware of this principle, was justifiably concerned. He knew that God would fulfill His part of the promise, but he did not know if his descendants ? who were expected to conquer the Land of Israel in the future ? would do their part.
This is a complicated stance. People of faith tend to trust God and assign Him missions that remove responsibility for their own actions. Abraham bequeathed to us a different sort of faith. He knew how to take responsibility for what occurred around him; he knew how to go out to battle with enemies; simultaneously ? he learned to devotedly open his home to guests. He was deeply involved in society and did not shirk responsibilities. He did not use faith as an escape from doing what he thought a person should do.
Only when a person does what is expected of him and takes responsibility for his actions can he trust God to do His part to make those actions successful.