1 Kings 2:26,27

(26) В¶ And unto Abiathar the priest said the king, Get thee to Anathoth, unto thine own fields; for thou art worthy of death: but I will not at this time put thee to death, because thou barest the ark of the Lord GOD before David my father, and because thou hast been afflicted in all wherein my father was afflicted. (27) So Solomon thrust out Abiathar from being priest unto the LORD; that he might fulfil the word of the LORD, which he spake concerning the house of Eli in Shiloh.

I do not presume to say as much, but yet I think it is likely, that Abiathar was at the bottom of Adonijah's proposal concerning Abishag; for Solomon, in his answer to his mother Bath-sheba, seems to hint at it in 1 Kings 2:22. But the degradation of Abiathar from the priest's office became a confirmation of what God had threatened concerning the house of Eli. Abiathar was the last high priest of that family; which, though predicted fourscore years before, was not confirmed until now. However slow, yet God's judgments are sure. The apostle makes a striking observation upon it, 2 Peter 3:8. How gracious Solomon appears in his dismission of Abiathar. He reminds him of his attachment to his father, and therefore deals gently by him. Think, Reader, in what a multitude of instances the Lord Jesus deals thus with sinners, and how gracious he is in the midst of judgment.