Parashas Toldos · Passuk 26:15
And the Philistines stopped up all the wells which his father’s servants had dug in the days of Avraham his father, filling them with earth.
Rashi on Bereishis 26:15 (classical source on this passuk; not listed as a numbered Torah Temimah unit here).
Lemma / focus: סתמום פלשתים.
English: Because they said: They are a danger to us because of the troops that come upon us.
Derash on the verse (Rashi) — not a formal named middah of the 13: the motive for stopping the wells is supplied as fear of marauding bands.
The Philistines stopped the wells dug in Avraham’s day, saying they brought danger from raiding troops.