Jamieson, Fausset and Brown on Genesis 26:12

12. Then Isaac sowed in that land--During his sojourn in that district he farmed a piece of land, which, by the blessing of God on his skill and industry, was very productive (Is 65:13; Psa 37:19); and by his plentiful returns he increased so rapidly in wealth and influence that the Philistines, afraid or envious of his prosperity, obliged him to leave the place (Pr 27:4; Ec 4:4). This may receive illustration from the fact that many Syrian shepherds at this day settle for a year or two in a place, rent some ground, in the produce of which they trade with the neighboring market, till the owners, through jealousy of their growing substance, refuse to renew their lease and compel them to remove elsewhere.