1 Kings 2:12-25
"12 So Solomon sat on the throne of David his father, and his kingdom was firmly established.
13 Then Adonijah the son of Haggith came to Bathsheba the mother of Solomon. And she said, “Do you come peacefully?” He said, “Peacefully.”14 Then he said, “I have something to say to you.” She said, “Speak.” 15 He said, “You know that the kingdom was mine, and that all Israel fully expected me to reign. However, the kingdom has turned about and become my brother's, for it was his from the Lord. 16 And now I have one request to make of you; do not refuse me.” She said to him, “Speak.” 17 And he said, “Please ask King Solomon—he will not refuse you—to give me Abishag the Shunammite as my wife.” 18 Bathsheba said, “Very well; I will speak for you to the king.”
19 So Bathsheba went to King Solomon to speak to him on behalf of Adonijah. And the king rose to meet her and bowed down to her. Then he sat on his throne and had a seat brought for the king's mother, and she sat on his right. 20 Then she said, “I have one small request to make of you; do not refuse me.” And the king said to her, “Make your request, my mother, for I will not refuse you.” 21 She said, “Let Abishag the Shunammite be given to Adonijah your brother as his wife.” 22 King Solomon answered his mother, “And why do you ask Abishag the Shunammite for Adonijah? Ask for him the kingdom also, for he is my older brother, and on his side are Abiathar the priest and Joab the son of Zeruiah.” 23 Then King Solomon swore by the Lord, saying, “God do so to me and more also if this word does not cost Adonijah his life! 24 Now therefore as the Lord lives, who has established me and placed me on the throne of David my father, and who has made me a house, as he promised, Adonijah shall be put to death today.” 25 So King Solomon sent Benaiah the son of Jehoiada, and he struck him down, and he died."
A little background knowledge will help us to understand the seeming severity of Solomon's punishment of Adonijah for presuming to ask for Abishag the Shunamite. Commentaries tell us that it was a universal eastern custom for a king's wives to be taken by his successor or rival (See 2 Samuel 16:21, where Ahitophel counselled Absalom to go in to his father's concubines). If, then, Adonijah had publicly espoused Abishag, it would have been a virtual renewal of his claim to the throne, and it is clear that Solomon viewed his request in this light (22) - 'Ask for him the kingdom also' - and acted accordingly. It was nothing more than a bare-faced attempt to renew his treasonable activities, and as such brought final disaster upon him. One would have thought that having once been defeated and had his life spared by the clemency of the king, he would have been content to live quietly, thankful for such favour, but no, he must make another ill-advised attempt to reinstate himself on the throne. From this we may learn that to be humiliated does not always make a man humble, but on the contrary sometimes drives him nearly mad with a perverse determination to assert himself, however foolhardy it may be and at whatever cost. Such men are dangerous, and they had better be dealt with, summarily. But more. It is clear that Adonijah mistook Solomon's meekness and magnanimity in showing clemency to him as weakness. This is a very common error that evil men make, Merciless themselves, they cannot understand mercy in others and despise it as something to be presumed upon. Never did he miscalculate more disastrously, he suffered the just reward of his rash folly and forfeited his life by rebelling against the divine will.