TT #82 · Parashas Vayeira · Passuk 21:7
And she said, “Who would have said to Avraham that Sarah would nurse children? For I have borne him a son in his old age.”
Torah Temimah points to Bava Metzia 87a. E-Daf · Sefaria — Bava Metzia 87a
TT lemma: היניקה בנים שרה.
“Sarah would nurse children.” How many children did Sarah nurse? Rabbi Levi said: Because the nations of the world were murmuring, “See this old man and old woman who brought a foundling from the marketplace and say, ‘He is our son,’” what did Avraham do? He invited all the great men of the generation, and Sarah invited their wives, and each brought her child without her wet-nurse. A miracle was performed for Sarah our mother, and her breasts opened like two fountains, and she nursed them all.
Derash on the verse (Bavli sugya) — not a formal named middah of the 13. The plural form is expanded into a narrative of miraculous public nursing.
Sarah nursed many infants at once to refute the claim that Yitzchak was a foundling; her breasts became like two fountains by miracle.