Yoav's Fierce Loyalty to David and Himself

Sheva Ben Bichri declared another rebellion, Amasa (David’s new chief of staff and Yoav’s replacement) joins in. David dispatches Yoav’s hot-headed brother Avishai to deal with the revolt.  Immediately we see that it is Yoav who arranges to assassinate Amasa, who happens to be his cousin, pretending to be interested in joining the revolt, and leaning over to kiss Amasa until suddenly grabbing hold of his beard and plunging a sword into him. Yoav continues to lead the charge and gets Sheva Ben Bichri.  Very typical of Yoav, fiercely loyal to his king even if he could have rightly felt mistreated.  He was able to think for himself to  go beyond or even violate what he perceives as poorly devised orders but only in cases where those violations coincide with his own self-interest.