Matthew Poole and continuators on 2 Samuel 3:19

19 And Abner also spake in the ears of Benjamin : and Abner went also to speak in the ears of David in Hebron, all that seemed good to Israel, and that seemed good to the whole house of Benjamin.

To these he particularly applies himself, because they might be thought most kind to Saul and his House, and most loth to let the Kingdom go out of their own Tribe; and therefore it was necessary that he should use all his art and power with them, to persuade them to a compliance with his design; and besides, they were a Valiant Tribe, and bordering upon Iudah, and situate between them and the other Tribes; and therefore the winning of them, would be of mighty concernment to bring in all the rest.