For all, &c. Some codices, 'with one early printed edition, read "When in all the house of my father were none other than dead men".
dead men. Hebrew men of death: i.e. doomed men. Hebrew. 'enosh. App-14.
What right... ? Figure of speech Erotesis (App-6), to emphasise the free grace of David.
Why speakest... ? Figure of speech Erotesis (App-8), to show dissatisfaction with Mephibosheth's defence. Hence his division of Saul's estate. See note on 2 Samuel 19:26.