12. I will set up thy seed after thee, &c.—It is customary for the oldest son born after the father's succession to the throne to succeed him in his dignity as king. David had several sons by Bath-sheba born after his removal to Jerusalem (2Sa 5:14-16; compare 1Ch 3:5). But by a special ordinance and promise of God, his successor was to be a son born after this time; and the departure from the established usage of the East in fixing the succession, can be accounted for on no other known ground, except the fulfilment of the divine promise.