וכל הבארות אשר חפרו

And the Philistines stopped up all the wells which his father’s servants had dug in the days of his father Abraham, filling them with earth.

Isaac dug anew the wells which had been dug in the days of his father Abraham and which the Philistines had stopped up after Abraham’s death; and he gave them the same names that his father had given them.

סתמום פלשתים THE PHILISTINES STOPPED THEM, saying, “They may become a source of danger to us because of marauding troops that may invade us” (i.e.,they may invade our country to obtain possession of the wells, or if they invade us for any other reason they will be able to find a supply of water). (Tosafot Sotah 10.) The rendering of the Targum טמונין means “stopping up” and we find it in the language of the Talmud (Pesachim 42a) “Chokes up (מטמטם) the heart”.