1 Kings 1:5

Adonijah. The fourth son of David (2 Sam. 3:4; 1 Chron. 3:2). The elder sons, Amnon and Absalom were dead, and Chileab presumably so, for nothing further is heard of him. Thus Adonijah seemed next in line for the throne.

I will be king. Adonijah no doubt alleged that he had a just claim to the throne. Presuming upon his seniority and puffed up with pride, he determined to take what steps were necessary to secure the kingdom. Even though he must have known of his father’s plans, he was willing to secure the throne by force, if necessary, against what obviously was the divine arrangement (1 Chron. 22:5-9). The younger brother Solomon was better qualified than Adonijah to serve as ruler of Israel (PP 749), but the elder was determined that he would be king, no matter what the consequences might be to the country or to those who might be persuaded to throw in their lot with him. The results are always tragic when reason and discretion are thrown to the winds in the service of self.