Why did Solomon remove abiathar from being priest?

Solomon removed Abiathar from being priest primarily because Abiathar supported Adonijah's claim to the throne over Solomon, undermining Solomon's authority. This act fulfilled a prophecy against the house of Eli, as Abiathar was a descendant of Eli, and it was seen as a necessary step to consolidate Solomon's rule and eliminate potential rivals. Additionally, Abiathar's actions were viewed as a breach of loyalty, prompting Solomon to replace him with Zadok, who remained faithful.