Parshat Chayei Sarah

The life of Sarah was one hundred years, twenty years and seven years Bereshit 23:1

At the age of twenty she was like age seven in beauty, and at the age of one hundred she was like age twenty in piety. [Another version: at one hundred she was like twenty in beauty, and at twenty she was like seven in piety.]

Rashi; Midrash Rabbah

Why does the Torah split up the tally of her years into three parts (“one hundred years,” “twenty years” and “seven years”)? To tell us that every day of her life was the equivalent of them all. At the age of one hundred years she was like age twenty in strength, and at age twenty she was like age seven in modesty and purity; at age seven she was like age twenty in intelligence, and at age twenty she was like age one hundred in righteousness.
 Midrash HaGadol