TT #26 · Parashas Vayeira · Passuk 18:12
And Sarah laughed within herself, saying, “After I have withered, shall I have pleasure, and my lord is old?”
Torah Temimah points to Megillah 9a. E-Daf · Sefaria — Megillah 9a
TT lemma: בקרבה.
“Within herself.” There was an incident with King Ptolemy who gathered seventy-two elders and placed them in seventy-two houses and said to each one, “Write for me the Torah of Moshe your teacher.” The Holy One, blessed be He, put counsel into the heart of each one, and they wrote for him “And Sarah laughed among her relatives.”
Derash on the verse (Bavli sugya) — not a formal named middah of the 13. The change made for the Greek translation preserves the dignity of the matriarch.
When translating for Ptolemy the Sages wrote “among her relatives” instead of “within herself,” protecting Sarah from the appearance of private mockery.