Isaac ended up doing the same thing.
Only it got worse.
Why would Isaac do this? It did not reap any benefits for his parents. In fact, it would seem to be a humiliating situation to be caught doing such a thing. Isaac definitely experienced for himself the shame of this decision. A PUBLIC PROCLAMATION of his lie was made!
It's possible that in relaying the story "of this crazy thing we did one time" to their son, they did not manage to present it in a negative light.
I've seen parents inadvertently talk about their life before Christ in a way that makes it seem so fun, and glittery, and romantic to their kids.
I think it is very important to talk about our past with our children. They should know our mistakes. But I think we should be cautious and aware that we are not romanticizing the past in how we relay this information.
As with Abraham to Isaac, the situation gets worse from generation to generation. Abraham was founding his lie on a partial truth; Sarah WAS his half-sister. For Isaac to repeat this behavior he had to straight-up LIE. In Abraham's case, God stepped in and intervened by telling the king to not touch Sarah. In Isaac's case, God didn't touch that mess. If the king hadn't seen them fondling each other in what they thought was a hidden place, there's no telling what disaster would have insued. And as mentioned before, when the king denounced Isaac, he did it loudly and to his entire nation. I'm not sure what your opinion is when a news outlet reveals a politician has been blatantly lying to the public about a matter, but I'm certain that's how the population felt about Isaac.
I have mad props for Abraham's endurance and faith. But I wish, for Isaac's reputation sake, that he'd have said, "Don't ever do that. Be honest and forthright and trust God to protect you, son."
Let us not giggle when we tell our kids about our foolishness while drunk or on drugs. Let us not high-five each other in conveying stories of narrow escapes. Let us soberly tell our children the damage we caused in our ignorant state. And let us wrap up those stories by telling them how thankful we are to not be living in that destructive place of darkness. Let's make sure they KNOW that because of the price Christ paid on Calvary to redeem us from our stupidity, that every generation henceforth will live in joyful humility and service to Jesus.