Charles Ellicott Commentary 2 Samuel 12:8

"and I gave thee thy master`s house, and thy master`s wives into thy bosom, and gave thee the house of Israel and of Judah; and if that had been too little, I would have added unto thee such and such things." — 2 Samuel 12:8 (ASV)

Your master’s wives. —In 2 Samuel 12:7–8 the prophet enumerates the chief favors and blessings shown to David, and these are so brought out as to show not only his base ingratitude, but also the unreasonableness of this particular sin. We are told of only one wife of Saul (1 Samuel 14:50) and of one concubine (2 Samuel 3:7) who was taken by Abner. If he had others, David certainly could not have taken them until more than seven and a half years after Saul’s death. The prophet refers to the Near Eastern custom that the new king had a right to the harem of his predecessor.