Parashas Chayei Sarah · Passuk 24:6
Avraham answered him, “On no account must you take my son back there!
Classical / Rashi-style on the prohibition of return (classical source on this passuk; not listed as a numbered Torah Temimah unit here).
Lemma / focus: השמר לך פן תשיב.
English: “Take care” — a strict warning not to return Yitzchak to the land of Avraham’s birth.
Derash on the verse (plain sense with classical emphasis) — not a formal named middah of the 13: the doubled warning is read as an absolute bar on returning the son to the old land.
Avraham strictly forbids taking Yitzchak back to the land of his own birth; the son of the covenant is not to leave the land that was promised.