In Parashat Toledot the Torah informs us that after Avraham's death, the Pelishtim (Philistines) stuffed the wells of water that he had dug in the Negev, and his son, Yitzchak, now digs them anew (26:15,18). At first glance, this conduct of the Pelishtim seems totally irrational and self-destructive. We can easily understand the incident briefly recorded earlier, in Parashat Vayera (21:25), where servants of the Philistine king, Avimelekh, stole one of Avraham's wells and claimed rightful ownership over it.