Genesis 20 -- He is my brother

Genesis 20:1 From there Abraham traveled to the region of the Negev and settled between Kadesh and Shur. While he lived in Gerar, 2 Abraham said about his wife Sarah, “She is my sister.”So Abimelech king of Gerar had Sarah brought to him.
3 But God came to Abimelech in a dream by night and said to him, “You are about to die because of the woman you have taken, for she is a married woman.”
4 Now Abimelech had not approached her, so he said, “Lord, would You destroy a nation even though it is innocent? 5 Didn’t he himself say to me, ‘She is my sister’? And she herself said, ‘He is my brother.’ I did this with a clear conscience and clean hands.”
6 Then God said to him in the dream, “Yes, I know that you did this with a clear conscience. I have also kept you from sinning against Me. Therefore I have not let you touch her. 7 Now return the man’s wife, for he is a prophet, and he will pray for you and you will live. But if you do not return her, know that you will certainly die, you and all who are yours.”
8 Early in the morning Abimelech got up, called all his servants together, and personally told them all these things, and the men were terrified.
9 Then Abimelech called Abraham in and said to him, “What have you done to us? How did I sin against you that you have brought such enormous guilt on me and on my kingdom? You have done things to me that should never be done.” 10 Abimelech also said to Abraham, “What did you intend when you did this thing?”
11 Abraham replied, “I thought, ‘There is absolutely no fear of God in this place. They will kill me because of my wife.’ 12 Besides, she really is my sister, the daughter of my father though not the daughter of my mother, and she became my wife. 13 So when God had me wander from my father’s house, I said to her: Show your loyalty to me wherever we go and say about me: ‘He’s my brother.’”
14 Then Abimelech took sheep and cattle and male and female slaves, gave them to Abraham, and returned his wife Sarah to him. 15 Abimelech said, “Look, my land is before you. Settle wherever you want.” 16 And he said to Sarah, “Look, I am giving your brother 1,000 pieces of silver. It is a verification of your honor to all who are with you. You are fully vindicated.”
17 Then Abraham prayed to God, and God healed Abimelech, his wife, and his female slaves so that they could bear children, 18 for the Lord had completely closed all the wombs in Abimelech’s household on account of Sarah, Abraham’s wife.

So, Abraham told his wife to again deny he was her husband. First with Pharoah and now with Abimelech. Abraham did this out of fear for his life. The Lord was merciful to the King and warned him of who Sarah was before he took her. The King obeyed the warning and returned Sarah to Abraham. He was understandably upset at Abraham for not telling him that Sarah was his wife. Again though, we see Abraham did not lie. Sarah is his sister. They have the same father. Through this event, Abimelech and his family were blessed by God through Abraham's prayer.

In this passage we see Sarah's  submission to her husband when she willingly tells the king that she is Abraham's sister.  Abraham told her to "Show your loyalty to me wherever we go and say about me: ‘He’s my brother.'"  She obeyed him and did this.

1 Peter 3:5 For in the past, the holy women who put their hope in God also beautified themselves in this way, submitting to their own husbands, 6 just as Sarah obeyed Abraham, calling him lord. You have become her children when you do what is good and are not frightened by anything alarming.

This passage, though referencing a slightly different story, shows that by submitting to our husband's, we become children of Sarah.  Sarah was the mother of the chosen people.  We, as Christians, are also God's chosen people through Christ.