Portion of Hayyei Sarah (Genesis 23:1). "The LORD knows the days of the blameless, and their inheritance shall be forever" (Psalms 37:18). Just as they are blameless [tamim, whole], so are their years whole. At twenty she was like one of seven in beauty; at one hundred she was like one of twenty in freedom from sin.
The LORD Knows the Days of the Blameless and Sarah's Whole Years
Yalkut Shimoni on Torah 102:6
פרשת חיי שרה(בראשית כג א) (תהלים לז, יח) "יוֹדֵעַ ה' יְמֵי תְמִימִים וְנַחֲלָתָם לְעוֹלָם תִּהְיֶה" כְּשֵׁם שֶׁהֵם תְּמִימִים, כָּךְ שְׁנוֹתֵיהֶן תְּמִימִים. בַּת עֶשְׂרִים כְּבַת שֶׁבַע לְנוֹי, בַּת מֵאָה כְּבַת עֶשְׂרִים לְחֵטְא.