51 Then Solomon was told, “Adonijah is afraid of King Solomon and is clinging to the horns of the altar. He says, ‘Let King Solomon swear to me today that he will not put his servant to death with the sword.’ ”

Read 1 Kings 1:51 Using Other Translations

And it was told Solomon, saying, Behold, Adonijah feareth king Solomon: for, lo, he hath caught hold on the horns of the altar, saying, Let king Solomon swear unto me to day that he will not slay his servant with the sword.
Then it was told Solomon, "Behold, Adonijah fears King Solomon, for behold, he has laid hold of the horns of the altar, saying, 'Let King Solomon swear to me first that he will not put his servant to death with the sword.'"
Word soon reached Solomon that Adonijah had seized the horns of the altar in fear, and that he was pleading, “Let King Solomon swear today that he will not kill me!”