This may well be reckoned amongst David's miscarriages, the multiplication of wives being expressly forbidden to the king, Deuteronomy 17:17. The use of it seems to have been his policy, that hereby he might enlarge his family, and strengthen his interest by alliances with so many considerable families. And the number of wives being not limited, Deu 17, he might conceive this was no transgression of that law.
Related Commentaries of 2 Samuel 5:13
2 Samuel 5:13
13 And David took him more concubines and wives out of Jerusalem, after he was come from Hebron: and there were yet sons and daughters born to David.