1 Kings 2:20-22

20Then she said, I desire one small petition of thee; refuse me not. And the king said to her, Ask, my mother, for I will not refuse thee.

21And she said, Let Abishag the Shunammite be given to Adonijah thy brother as wife.

22And king Solomon answered and said to his mother, And why dost thou ask Abishag the Shunammite for Adonijah? ask for him the kingdom also; for he is mine elder brother; even for him, and for Abiathar the priest, and for Joab the son of Zeruiah.