Joab: Son of David's Sister: Supports Adonijah As Successor to David
Source: Nav
1 Kings 1:7
So Adonijah conferred with Joab son of Zeruiah and with Abiathar the priest, who supported him.
1 Kings 2:28
When the news reached Joab, who had conspired with Adonijah but not with Absalom, he fled to the tent of the LORD and took hold of the horns of the altar.