We read the terrible predictions that will befall the Jewish people if they abandon the Torah. Towards the end, however, we are told: VEZACHARTI ET BRITI YAAKOV. “Then I will remember My covenant with Yaakov, and also My covenant with Yitzchak and also My covenant with Avraham …” (Lev. 26,42) Hashem will remember the covenant He made with the forefathers to give their descendants the Land of Israel.
What is strange about this Pasuk is that when mentioning the forefathers they are mentioned in reverse order, first Yaakov then Yitzchak and then Avraham. They should have been mention in chronological order, starting with Avraham.
Someone once told a parable to explain it. A boy bought candy in a store and paid for his purchase. The storekeeper then gave him a few extra candies without charging him. Another boy standing nearby saw this and said to the storekeeper if you gave him free candy give me some as well. The storekeeper told him that the boy had purchased and he gave him extra. You have not bought anything, why should I give you free candy.
Likewise, had the Pasuk started with Avraham and Yitzchak, the descendants of Esav and Ishmael would have come with a claim that they too should get a share in the land. Their forefathers had followed the teachings of Hashem. The Pasuk started with Yaakov since all his descendants remained in the Jewish fold. They deserved the land. No one else can claim the same gift from Hashem. The gifts to Avraham and Yitzchak’s descendant were only added on to those of Yaakov. Yaakov’s descendants deserved the extra gifts.