Abraham and Sara are the quintessential wandering Jews. As soon as they get one place, they pull up stakes and move. They get to Canaan and then immediately go to Egypt.
While in Egypt Abraham gets nervous and asks Sara to “cover” for him. He tells her “Say you are my sister” This way they won’t kill me to get you. Pharoah finds out about Sara’s availability and beauty and she is taken to him. An angel is sent to strike Pharoah with a plague to stop him from being with Sara.
The Kli Yakar asks a great question: Where is Pharoah’s sin and Why is Pharaoh punished? Abraham and Sara are telling everyone they are not married. Sara is available according to them. Pharoah has good reason to believe she is his sister acccording to Kli Yakar’s question.
The Klii Yakar answer is that Sara tells Pharoah the truth privately after spreading a different story to everyone else. Pharoah thinks she is just playing coy. What a mess. Ultimately the plague is needed to keep Pharoah off of her. Therefore, a plague is needed and Pharoah is stricken.
The SD take on this is as follows: This is a hot mess because Abraham could have shown some belief that GD and know he and Sara would be protected. Abraham would not have started bad blood in Egypt if he just told the truth. The Kli Yakar’s question really highlights the lack of faith exhibited by Abraham. It almost-maybe makes Pharoah the victim. How can Pharoah know who is telling the truth.
The bottom line is that Faith in Hashem keeps everything straight,