Genesis 26:1-5, 12-17

And there was a famine in the land, beside the first famine that was in the days of Abraham. And Isaac went unto Abimelech king of the Philistines unto Gerar. And the LORD appeared unto him, and said, Go not down into Egypt; dwell in the land which I shall tell thee of: sojourn in this land, and I will be with thee, and will bless thee; for unto thee, and unto thy seed, I will give all these countries, and I will perform the oath which I sware unto Abraham thy father; and I will make thy seed to multiply as the stars of heaven, and will give unto thy seed all these countries; and in thy seed shall all the nations of the earth be blessed; because that Abraham obeyed my voice, and kept my charge, my commandments, my statutes, and my laws.

Then Isaac sowed in that land, and received in the same year an hundredfold: and the LORD blessed him. And the man waxed great, and went forward, and grew until he became very great: for he had possession of flocks, and possession of herds, and great store of servants: and the Philistines envied him. For all the wells which his father's servants had digged in the days of Abraham his father, the Philistines had stopped them, and filled them with earth. And Abimelech said unto Isaac, Go from us; for thou art much mightier than we. And Isaac departed thence, and pitched his tent in the valley of Gerar, and dwelt there.