Genesis 20:2

"Abraham moved from there to the southern land," the text goes on, "and dwelt between Kadesh and Shur, sojourning at Gerar." Moved on from where? From the place where he was camped, where he was given the privilege of hosting the Lord of all with the angels. Moving from there, the text says, "he sojourned in Gerar." Notice the life of these good people, how restrained and austere it was, how they shifted place with ease and conducted their life like pilgrims or nomads, pitching their tent at one time in this place, at another in that, as though living in a strange land. They are unlike us, who live in a strange land as though in our home country, erecting extravagant mansions, porches and covered walks, possessing land, building baths and countless other luxuries.By contrast see the good man holding all his possessions in his household and flocks alone. [He is] never staying in one place but at one time pitching his tent in Bethel, at another by the oak of Mamre, at another going down to Egypt and now camping at Gerar, submitting to all this with ease and giving clear evidence in every way of gratitude to his own Lord. Despite such wonderful promises and guarantees given him by God, he saw himself beset by such imposing difficulties and encountering such varied and differing trials. Yet he stood unshaken like some piece of steel, showing his godly attitude and proving no less resolute in any of the problems surrounding him. See in the present instance too, dearly beloved, the kind of trial that befell him at Gerar and the wonderful caliber of the just man's virtue. What everyone else found unbearable and could not bring themselves to accept he put up with without complaint and without demanding from the Lord explanation of what happened, as many people do, even though weighed down with countless burdens of sin.

I think, therefore, that Sarah, which means "princess" or "one who governs empires," represents aretē, which is the virtue of the soul. This virtue then is joined to and clings to a wise and faithful man, even as that wise man who said of wisdom, "I have desired to take her for my spouse." For this reason therefore God says to Abraham, "In all that Sarah has said to you, listen to her voice."

And he said of Sarah his wife, She is my sister. So Abimelech king of Gerar sent, and took her. Why Abraham said this about Sarah, and whence it should be believed that she, although taken into the king's house, was by no means touched …

And Abraham said of Sarah his wife. In this history, the Holy Spirit presents to us a remarkable instance, both of the infirmity of man, and of the grace of God. It is a common proverb, that even fools become wise by suffering evil.

The peril that Sarah was brought into by this means: The king of Gerar sent, and took her to his house, in order to the taking of her to his bed. Note, The sin of one often occasions the sin of others; he that breaks the hedge of God's commandments opens a gap to he knows not how many; the beginning of sin is as the letting forth of water.