2 Samuel 3:25

Thou knowest Abner, the son of Ner, that he came to deceive thee, with an evil and hostile purpose, and to know thy going out and thy coming in, and to know all that thou doest. In his reproach of David, Joab accused Abner of being a spy, a traitor, who was seeking information favorable to his schemes. The object was, of course, to make David so unfavorably disposed toward Abner that he would overlook the revenge which Joab was planning.