There was a famine in the land, besides the first famine that was in the days of Abraham.
And Isaac went to Abimelech king of the Philistines to Gerar.
Abimelech was a title for the ruler of the Philistines, like Pharaoh was the title for the ruler of that Egyptians. This Abimelech is probably different from the one with whom Abraham made a covenant, since that was 60 to 100 years earlier.
The Lord appeared to Isaac.
The Lord: Do not go down into Egypt; dwell in the land of which I shall tell you. Sojourn in this land, and I will be with you, and will bless you; for I will give all these countries to you and to your seed, and I will perform the oath which I swore to Abraham your father. And I will make your seed to multiply as the stars of heaven, and will give to your seed all these countries; and in your seed shall all the nations of the earth be blessed, because Abraham obeyed my voice and kept my charge, my commandments, my statutes, and my laws.
Do you recognize these words? This is the promise God made to Abraham (Genesis 17:6-8, 22:17-18), now he is making the same promise to Isaac, Abraham’s seed.
And Isaac dwelt in Gerar.
The men of the place asked him of his wife.
Isaac: She is my sister.
Isaac feared to say, She is my wife.
Isaac: Lest the men of the place should kill me for Rebekah.
Rebekah was fair to look upon.
When Isaac had been there a long time, Abimelech king of the Philistines looked out of a window, and saw Isaac sporting with Rebekah his wife.
Abimelech called Isaac.
Abimelech: Of a surety she is your wife. Why did you say, She is my sister?
Isaac: Because I said, Lest I die for her.
Abimelech: What is this you have done to us? One of the people might lightly have lain with your wife, and you would have brought guiltiness on us.
Abimelech (to all his people): He that touches this man or his wife shall surely be put to death.
Does this situation sound familiar? It should. Twice Abraham was in the same situation. (Genesis 12,20) First in Egypt, then in Gerar like Isaac. Abraham did not lie when he said Sarah was his sister. She was his wife but also his half-sister. (Genesis 20:12) But Isaac did lie. Rebekah was not his sister.