1 Samuel 25:39

And when David heard that Nabal was dead, he said, Blessed be the LORD, that hath pleaded the cause of my reproach from the hand of Nabal, and hath kept his servant from evil: for the LORD hath returned the wickedness of Nabal upon his own head. And David sent and communed with Abigail, to take her to him to wife. The Lord hath returned the wickedness of Nabal upon his own head. If this was an expression of pleasure, and David's vindictive feelings were gratified by the intelligence of Nabal's death, it was an instance of human infirmity which we may lament; but perhaps he referred to the unmerited reproach (1 Samuel 25:10), and the contempt of God implied in it.

David sent and communed with Abigail, to take her to ... wife. This unceremonious proceeding was quite in the style of Eastern monarchs, who no sooner take a fancy for a lady than they despatch a messenger to intimate their royal wishes that she should henceforth reside in the palace; and her duty is implicitly to obey. David's conduct shows that the manners of the Eastern nations were already imitated by the great men in Israel; and that the morality of the times, which God permitted, gave its sanction to the practice of polygamy. His marriage with Abigail brought him a rich estate; and the fact of a woman in her wealthy circumstances so willingly forming a matrimonial relation with David, shows that the position he occupied, while expatriated in the wilderness, was far more elevated and comfortable than is generally imagined.