2 Samuel 4:8 - Matthew Poole's English Annotations on the Holy Bible

Which sought thy life, i.e. to destroy it, or take it away; as this phrase is used, 1 Samuel 20:1, 1 Samuel 23:15, and elsewhere. They thought their action not only blameless, but meritorious; because they had but executed justice upon Saul's house, and David's enemies, and made way for David's obtaining of his rights. It may seem strange they were not discouraged by David's punishing of the Amalekite for killing Saul, 2Sa 1, and by his sharp reproof of Joab for murdering Abner; but they thought the first case much differing from theirs, because Saul was anointed king by God; whereas Ish-bosheth was not, but was a mere usurper: and for the latter, they thought that David's sharp words proceeded rather from art and policy, than from any real dislike of thee thing; which they judged, because David contented himself with words, and Joab did not only go unpunished, but continued in his former place and power.