כלי יקר — וזכרתי את בריתי יעקוב... בריתי יצחק... בריתי אברהם

Q — Why does the verse list the avot in *reverse* order — Yaakov, Yitzchak, Avraham — when everywhere else Avraham comes first?

A — Kli Yakar offers a mashal of three coin-purses. Imagine three identical purses, equally full; you start drawing from the first in Nisan, the second in Iyar, the third in Sivan. The third purse will always be fullest. The same is true of avot-merit: Bnei Yisrael have been drawing on Avraham's zechut the longest, and so it would be reasonable to assume his merit is most depleted. The verse therefore says 'לא זו אף זו': not only Yaakov's recent merit (obviously still abundant), but even Yitzchak's older merit — and even Avraham's ancient one, which one might have thought was used up. 'בריתי אברהם' is preserved for every generation, despite the centuries of withdrawal.