Thereafter the king invited Isaac to settle in his domains, and he assigned fields and vineyards to him for cultivation, the best the land afforded. But Isaac was not self-interested. The tithe of all he possessed he gave to the poor of Gerar. Thus he was the first to introduce the law of tithing for the poor, as his father Abraham had been the first to separate the priests' portion from his fortune.
Isaac was rewarded by abundant harvests; the land yielded a hundred times more than was expected, though the soil was barren and the year unfruitful. He grew so rich that people wished to have "the dung from Isaac's she-mules rather than Abimelech's gold and silver." But his wealth called forth the envy of the Philistines, for it is characteristic of the wicked that they begrudge their fellow-men the good, and rejoice when they see evil descend upon them, and envy brings hatred in its wake, and so the Philistines first envied Isaac, and then hated him.
In their enmity toward him, they stopped the wells which Abraham had had his servants dig. Thus they broke their covenant with Abraham and were faithless, and they have only themselves to blame if they were exterminated later on by the Israelites.