Genesis 26:9
And Abimelech called Isaac, and said, Behold, of a surety she is thy wife: and how saidst thou, She is my sister? And Isaac said unto him, Because I said, Lest I die for her. And Abimelech called Isaac, and said, Behold, of a surety she is thy wife: and how saidst thou, She is my sister? And Isaac said unto him, Because I said, Lest I die for her.
Abimelech confronted Isaac after discovering that Rebekah was his wife and not his sister, rebuking him sternly for the deception, and Isaac admitted he had called her his sister because he feared he would be killed on her account. Abimelech, king of Gerar, had taken her supposing her to be unmarried, and knew that taking another man's wife would bring guilt upon himself and his people and kingdom. His warning that one of the people might have lain with her shows that adultery was already recognized as a serious, sinful, guilt-bringing wrong that Isaac's lie had risked bringing upon them. The account therefore proves that the seventh commandment was given and well known among mankind long before it was spoken on Sinai, in the course of God's providential dealings over Abraham's family as the chosen line through whom the promised Seed would come.
Narrative Setting and Meaning
Genesis 26:9 belongs to the chapter in which famine carries Isaac into the land of the Philistines, where he receives abundant blessing in that land and becomes great under the Lord's blessing. There he has differences with the Philistines, yields more than justice requires, and is blessed by God in consequence, with the chapter closing with an account of Esau's marriages. The setting is Isaac's sojourn and increase in the country of the Philistines in that time of famine.
Abimelech confronts Isaac after discovering that Rebekah is his wife and not his sister. The encounter brings a stern rebuke to Isaac. Isaac admits that he called her his sister and lied because he feared he would die and be killed on her account, showing fear leading him to deceive.
The verse is part of that chapter's account of Isaac's conduct in which Isaac follows his father's example. It belongs to the same family history in which Genesis 26:3-5 says Abraham kept God's commandments and laws, not to a list of three commands to Abraham. Genesis 26:9 belongs to the account in which God spoke to Isaac in an audible voice. This shows that after sin entered the world God instructed His people by an audible voice as one of the various times and manners in which He spoke to the fathers.
Doctrinal and Providential Lessons
Abimelech, king of Gerar, had taken Rebekah supposing her to be Isaac's sister and unmarried, and when he discovered she was Isaac's wife he rebuked Isaac for the deception. He knew that taking another man's wife would bring guilt upon himself and his people and upon his kingdom, and his warning that one of the people might have lain with her shows that Isaac would have brought that guiltiness upon them. Isaac's claim that she was his sister had put them at risk of committing that wrong, and Abimelech recognized that if someone had lain with her guilt would have fallen on his people. Adultery was thus already recognized among mankind in general as a serious, sinful, guilt-bringing wrong that Isaac's deception had risked bringing upon them.
The verse therefore proves that the seventh commandment, Thou shalt not commit adultery, was given and well known long before it was spoken on Sinai. Mankind in general knew that taking another man's wife was sinful, as Abimelech's accounting of Isaac for the deception demonstrates.
The verse belongs to the account of God's providential dealings with Abraham's family as the chosen line through which the promised Seed would come. It belongs to the demonstration of God's special providences over the progenitors of the promised Seed.