Genesis 13:16
And I will make thy seed as the dust of the earth: so that if a man can number the dust of the earth, then shall thy seed also be numbered. And I will make thy seed as the dust of the earth: so that if a man can number the dust of the earth, then shall thy seed also be numbered.
God pledged to make Abraham's offspring like the dust of the ground, a multitude so vast that if anyone could count the dust then they could count his descendants, which is to say they could not be counted at all. That pledge came after the parting from Lot as a renewal of promise, in which the whole country and land round about was given to Abraham and to his descendants with him. At the time Abraham was childless and supposed his servant might become his heir, yet he was assured that he himself should have a son and an heir of his own through whom the innumerable seed should come.
Abraham held that promise in mind when he was commanded to offer Isaac, the son in whom its fulfillment centered, so that the command appeared to cut off and destroy the very word on which his hope rested. He obeyed nevertheless, trusting that God was able to raise Isaac from the dead rather than let the promise fail. The landward side of the same promise likewise remained unpossessed in his lifetime, for he owned none of Canaan and even had to purchase a burial place for Sarah.
The full receiving of the inheritance still lies ahead, when after the purifying of the earth and its making new Abraham and his children shall receive title to their possessions. It is therefore an enduring inheritance in the renewed earth to be accepted by faith, not a ground for security in present earthly prosperity.