When the men there asked him about his wife, he told them, “She's my sister,” because he was afraid. He said to himself, “If I say she's my wife, the men here will kill me to get Rebekah, because she's so beautiful.”
Don't be afraid of those who can kill you physically, but can't kill you spiritually. Instead, be afraid of the one who can destroy you physically and spiritually in Gehenna.
But David said to himself, “One of these days Saul is going to get me. I think I'd better run away to the land of the Philistines. Then Saul will give up looking for me all over Israel and he won't catch me.”