Parashas Toldos · Passuk 26:4
I will make your offspring as numerous as the stars of heaven, and assign to your offspring all these lands, so that all the nations of the earth shall bless themselves by your offspring.
Rashi on Bereishis 26:4 (classical source on this passuk; not listed as a numbered Torah Temimah unit here).
Lemma / focus: והתברכו בזרעך.
English: A man says to his son, “May your offspring be like the offspring of Yitzchak”; and so throughout Scripture—and this is the father of them all.
Derash on the verse (Rashi) — not a formal named middah of the 13: the phrase is read as the paradigm of blessing oneself by another’s seed.
Nations will bless themselves by Yitzchak’s offspring—saying, “May your seed be like the seed of Yitzchak.”