Who was Abiathar in the Bible?

Abiathar was a high priest in the Hebrew Bible, and a son of Ahimelech. He is first mentioned in the book of 1 Samuel, where he served as a priest in the town of Nob, and provided David with the sacred bread and the sword of Goliath when David was fleeing from King Saul. Abiathar continued to support David even after Saul's death, and served as one of David's chief advisors and priests. Abiathar was eventually removed from his position as high priest by King Solomon due to his loyalty to Adonijah, who had attempted to overthrow Solomon. He died in Jerusalem and was buried there. Abiathar is notable for his role in the history of the Israelites, as well as for his loyalty to David. He is also remembered for his role as a priest, and for his role in the events surrounding the transition of power from Saul to David as the king of Israel.

first mention in the bible is in the book of 1 Samuel, chapter 22, verse 20.