Summary: Adonijah sought mercy and forgiveness while gripping the horns of the altar of sacrifice in the tabernacle. King Solomon had mercy upon his step-brother Adonijah. However...
The Horns of the Altar
(1 Kings 1:47-53) “…the king’s servants have gone to bless our lord King David, saying: ‘May God make the name of Solomon better than your name, and may He make his throne greater than your throne’ Then, the king bowed himself on the bed.  Also, the king said thus: ‘Blessed be the LORD God of Israel, who has given one to sit on my throne this day, while my eyes see it!’  So, all the guests who were with Adonijah were afraid, and arose, and each one went his way.  Now, Adonijah was afraid of Solomon; so he arose, and went and took hold of the horns of the altar.  And, it was told Solomon, saying,’ Indeed, Adonijah is afraid of King Solomon; for look, he has taken hold of the horns of the altar, saying, Let King Solomon swear to me today that he will not put his servant to death with the sword.’  Then Solomon said, ‘If he proves himself a worthy man, not one hair of him shall fall to the earth; but if wickedness is found in him, he shall die.’  So, King Solomon sent them to bring him down from the altar. And, he came and fell down before King Solomon; and Solomon said to him, ‘Go to your house.’”
Solomon was to be the king after David, but his elder brother – Adonijah – was preferred by Joab, the captain of the host, and by Abiathar, the priest; and, therefore, they conspired together, and tried to steal the throne and set up Adonijah as the next king of Israel. They utterly failed in this ill-conceived venture; and, when Solomon came to the throne, Adonijah feared for his life. He fled immediately fled to the horns of the altar at the tabernacle for shelter. Solomon permitted him to find sanctuary there, and forgave him his offence, and said that if he proved himself a worthy man he should live without further molestation. But, very soon, he began plotting again, and sought to undermine Solomon now that their venerable father was dead. It became, therefore, necessary –especially according to ancient philosophy and ideals – for Solomon to strike a heavy blow. However, Solomon chose to bring mercy and peace; only when it appeared to be sought honestly.
Then, we see in 1 Kings 2:28 that Adonijah went back onto his own commitment to peace with the reign of his younger brother Solomon. Adonijah – the 4th son of David and his wife Haggith – came to Solomon’s mother Bathsheba. He asked her to go before King Solomon and ask for a wife to be given unto him. However, it was the attitude Adonijah had in his royal query that cost him his very life.
(1 Kings 2:15) – “…You know that the kingdom was mine, and all Israel had set their expectations on me, that I should reign. However, the kingdom has been turned over, and has become my brother’s; for it was his from the LORD.” Then, we see the reaction of the king; and, just how swift and serious it was (1 Kings 2:18-23) – “’…Very well, I will speak for you to the king.’  Bathsheba, therefore, went to King Solomon, to speak to him for Adonijah. And, the king rose up to meet her and bowed down to her, and sat down on his throne and had a throne set for the king’s mother; so she sat at his right hand.  Then, she said: ‘I desire one small petition of you; do not refuse me.’ And, the king said to her, ‘Ask it, my mother, for I will not refuse you.’  So, she said: ‘Let Abishag the Shunammite be given to Adonijah your brother as wife.’  And, King Solomon answered and said to his mother, ‘Now why do you ask Abishag the Shunammite for Adonijah? Ask for him the kingdom also – for he is my older brother – for him, and for Abiathar the priest, and for Joab the son of Zeruiah.’  Then, King Solomon swore by the LORD, saying: ‘May God do so to me, and more also, if Adonijah has not spoken this word against his own life!’” In v. 25, we see Solomon’s death penalty met-out upon Adonijah – “So King Solomon sent by the hand of Benaiah the son of Jehoiada; and, he struck him down, and he died.”