Genesis 26:18

And Isaac digged again the wells of water, which they had digged in the days of Abraham his father; for the Philistines had stopped them after the death of Abraham: and he called their names after the names by which his father had called them.

Ver. 18. Isaac digged again the wells, &c.] Both for more certainty to find water - a scarce commodity in those hot countries; and because the labour was the easier, and his fight the better, since they had once been his father's.