Chasidut zu Bereschit 15:8

This is the aspect of "And he divided himself against them" (Genesis 14:15) which is said about Abraham at the time he chased after the kings. For Abraham revealed G-d's blessed providence in the world. Therefore, the essence of the fulfillment of the generations of the heavens and earth is through Abraham, as it is written (Genesis 2:4) "These are the generations of the heavens and the earth when they were created, בְּהִבָּרְאָם - meaning, through Abraham בְּאַבְרָהָם (Genesis Rabbah 2:4). Abraham revealed His blessed providence to the world; for the essence of the existence of the world is through this. Therefore, Abraham had the power to divide the night, in other words to break the night, which is the aspect of nullification of nature, the aspect of rising at midnight, as explained above. Then {Abraham} overpowered the four kings, which are the aspect of the four Malchuyot, as brought. The essence of their subjugation is through the nullification of nature, as explained above. Therefore, because he erred {by saying} what was written there (Genesis 15:8) "how will I know that I will inherit it?", the exile was decreed because of this, for it was a blemish in knowledge, which is the aspect of divine providence. The essence of knowledge is the aspect of divine providence. And divine providence, this is the aspect of the Land of Israel, the aspect of (Deuteronomy 11:12) "the eyes of Lord your God are always upon it", as Rebbe Nachman wrote in another place. Therefore, because he blemished the da'at/knowledge and blemished the Land of Israel, which is the aspect of divine providence, (Genesis 15:12) "a deep sleep fell upon Abram, and behold, a fright, a great darkness was falling upon him". Because he saw the strength of the exile, which is the aspect of 'a deep sleep', the aspect of darkness, the essence of their subjugation through the natural sciences, through the blemishing of divine providence, as explained above.

Going back once more to Genesis 15,8 when Avraham himself ‎had asked a question not i.e. revealing that He had not quite ‎understood G’d, as a result of which he was granted better ‎understanding, just as Avimelech here had concluded with ‎understanding and acknowledging the dimension of G’d as ‎אנכי‎, ‎the Talmud B’rachot 7 states that when Avraham posed the ‎question of ‎במה אדע‎, he had become the first person ever to ‎address G’d as ‎א-דני‎, “My Lord;” He had implied by this that G’d in ‎His capacity of ‎א-דני‎ was able to annul decrees. Noach had not ‎been aware that G’d could do this, and this is why he had not ‎bothered to appeal to G’d to annul the decree to annihilate ‎mankind. His predecessor Sheth, third son of Adam, himself a ‎‎tzaddik had also not known about this and therefore he had ‎remained silent when a third of the inhabited area of the globe ‎had been flooded in his day. The power of addressing this ‎dimension of G’d was given to Avraham as a reward for having ‎recognized G’d as possessing this dimension. It was Avraham’s ‎genius to recognize this quality of G’d although he addressed Him ‎as “My Lord.”‎

Genesis ‎15,8. “how can I be certain that I will inherit it?" (the land ‎of Canaan) When looking at these words superficially, we must ‎wonder how someone of Avram’s caliber could express doubt in ‎G’d’s promise being fulfilled. The very idea that Avram requested ‎some kind of visible token or miracle to confirm the fact that G’d ‎would keep His promise is revolting! Since when is G’d required to ‎confirm His prophecy by performing a miracle?
Furthermore, ‎if this was the meaning of Avram’s question, he should have ‎asked: “how do I know that You will give the land to me!” After ‎all, this was what G’d’s promise to him had sounded like. To the ‎average reader of the Torah, G’d’s words meant that the reason ‎G’d had saved Avram from Nimrod’s furnace was in order to give ‎him the land of Canaan. Besides, how does G’d’s answer that ‎Avram would die at a ripe old age long before the 400 years He ‎had spoken of would have ended, answer Avram’s question? How ‎is the promise that after 400 years of being strangers in a foreign ‎land, and slaves to wit, and that the fourth generation would ‎leave bondage with great riches, relevant to Avram’s ‎question?
If, according to the plain meaning of the text, G’d’s ‎answer included a punishment for Avram’s having questioned ‎that G’d would keep His promise the prediction that his offspring ‎would have to endure a period of enslavement in a foreign land, ‎before leaving their with great riches, how does the line ‎commencing with ‎ידוע תדע וגו'‏‎, contain even the remotest hint of ‎this? We do not find anywhere an allusion that Avram’s question ‎of ‎במה אדע כי אירשנה‎, “by means of what sign will I know that I will ‎inherit it,” was in any way inappropriate, much less punishable! ‎On the contrary, the assurance that Avram himself would not ‎share either the exile of the slavery but would die contentedly of ‎old age, sounds like the opposite of any punishment! The fact ‎that G’d implies that he will join his father in the hereafter ‎suggests that even Terach, Avram’s father, has a share in that ‎hereafter.
Rashi, who was so astounded at that verse, ‎concluded that in his old age, Terach had become a monotheist, a ‎repentant sinner.
At any rate, the suggestion that one of the ‎patriarchs, who are presented to us as the carriers of the legs of ‎merkavah, the Divine chariot, would be equated with Terach is too ‎mind-boggling to be considered seriously.