'Adversaries' in the Bible

And David said, What have I to do with you, ye sons of Zeruiah, that ye should this day be adversaries to me? Should there any man be put to death this day in Israel? for do not I know that I am this day king over Israel?

And Gad came to David, and told him, and said to him, Shall seven years of famine come to thee in thy land? or wilt thou flee three months before thine adversaries while they pursue thee? or shall there be three days' pestilence in thy land? Now be aware and consider what word I shall bring again to him that sent me.