Sefer HaIkkarim, Maamar 4 35:7ספר העקרים, מאמר ד ל״ה:ז׳
Since this belief is the most remarkable of the beliefs accepted by our people, it was placed right after the benediction of the Fathers. The expression, “abundant mercies,” is applied to resurrection, because the life of man is divided into three parts, the years of growth, the stationary years and the years of decline. In all these three periods God nourishes man and supports him in life with grace, kindness and mercy. Hence these three expressions are mentioned in Grace after Meals, which Moses composed for Israel, to correspond to the three periods mentioned. In the years of growth, when the assimilation of the food is great and exceeds the dissolution, there is no need of extraordinary kindness to keep the individual alive. Still, inasmuch as the assimilated food is altogether unlike the original fluid, some divine help is necessary, and the grace (hen) of God is sufficient. In the stationary years, when the dissolution is equal, or approximately so, to the assimilation, greater help is needed of divine kindness (hesed) to maintain life. Finally, in the years of decline, when the dissolution is much greater than the assimilation resulting from the food, man needs God’s mercy (rahamim) to maintain him alive. After death, neither grace, nor kindness, nor mercy is sufficient to bring man to life again, but there is need of great mercy, hence they say, “He reviveth the dead with great mercy.”
Notes by Rabbi Yehoshua Hartman on Gevurot Hashem 64:24פירושים והערות מהרב יהושע הרטמן על גבורות השם ס״ד:כ״ד
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Gevurot Hashem 64:4גבורות השם ס״ד:ד׳
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