Abraham asks Sarah to declare that she is his sister, lest the Egyptians kill him if it becomes known that he is her husband. The Sages discuss Abraham and Sarah’s descent to Egypt and the exchange between Abraham and the Egyptians.

“It was upon Abram’s arrival in Egypt, the Egyptians saw [the woman, that she was very fair.]” (Genesis 12:14). Where was Sarah? Abraham placed her in a chest to hide her, and locked her in it. Once they reached customs, the customs workers said to him: Pay the tariff. Abraham said: I will pay the tariff. [In order to encourage him to open his chest] they said to him: You are bearing vessels, [which carry a high tariff]. Abraham said: I will pay that of vessels. They said to him: You are bearing gold, [which carries an even higher tariff]. Abraham said: I will pay that of gold. They said to him: You are bearing silk, [which carries an even higher tariff]. Abraham said: I will pay that of silk. They said to him: You are bearing jewels, [which carry an even higher tariff]. Abraham said: I will pay that of jewels. They said to him: There is no way out of your opening the chest and showing what is in it. Once he opened it, the entire land of Egypt shone from Sarah’s radiance. (Bereshit Rabba 40)