Is the Covenant with Abraham Conditional or Unconditional?

Rabbi Abahu said in the name of Rabbi Eleazar: "Why was Abraham punished, and his children enslaved in Egypt for 210 years?"... Shmuel said: "Because he went too far in testing the attributes of the Holy Blessed One, as it is said, 'By what will I know that I will inherit it?'"

"By what will I know?" He did not ask Him for a sign. Rather he said before Him, "Let me know by what merit they will uphold it." The Holy Blessed One replied to him: "By the merit of the sacrifices."

And it is written, “And he said, O Lord God, How shall I know that I shall inherit it?” (Genesis 15:8). Abraham said before the Holy One, blessed be He: Master of the Universe, perhaps God forbid, Israel will sin before You and You will do to them as You did to the generation of the Flood and the generation of the Dispersal [of the world]? He answered: No.... He then said before Him: Master of the Universe: By what shall I know this? He said: “Take a heifer of three years old” etc. (Genesis 15:9). He then said before Him: Master of the Universe: This is very well for the time when the Temple will be standing, but in the time when there will be no Temple what will happen to them? He replied to him: I have already set for them the order of the sacrifices. Whenever they will read the section dealing with them, I will account it to them it as if they were bringing me an offering, and forgive all their sins.

"And he believed in Hashem, and He considered it righteous." Rashi interpreted: The Holy Blessed One considered Avram's faith as righteous and meritorious. But I do not understand what merit this is--why would he not believe in a faithful God? He was a prophet himself, and not someone who believed in false gods. And he believed in God so much that he was willing to sacrifice his only, beloved son! And he passed all the other tests. How could he not believe in God's good tidings?! Rather, the correct interpretation in my eyes is that he had faith in God, and he thought that, because of God's righteousness, God would give him children regardless--not because of his own particular merit or reward, even though God had assured him that "your reward will be very great." And from this point forward, he did not fear that any sin would override the promise. And even though in his original prophecy he thought that the covenant was conditional, according to the merit of his actions, now, because God promised him that he did not need to fear sin, and that He would give him children, he believed that God's word was true, and that God would not go back on it, it was God's righteousness, which is unbreakable.

In every generation a person must regard himself as though he personally had gone out of Egypt, as it is said: “And you shall tell your son in that day, saying: ‘It is because of what the Lord did for me when I came forth out of Egypt.’”