1 Kings 2:20-23

²⁰Then she said, I have one small request to make to you; do not say, No, to me. And the king said, Say on, my mother, for I will not say, No, to you.

²¹And she said, Let Abishag the Shunammite be given to Adonijah your brother for a wife.

²²Then King Solomon made answer and said to his mother, Why are you requesting me to give Abishag the Shunammite to Adonijah? Take the kingdom for him in addition, for he is my older brother, and Abiathar the priest and Joab, the son of Zeruiah, are on his side.

²³Then King Solomon took an oath by the Lord, saying, May God's punishment be on me if Adonijah does not give payment for these words with his life.