It happened, at the time of the return of the year, at the time when kings go out [to battle], that Joab led forth the army, and wasted the country of the children of Ammon, and came and besieged Rabbah. But David stayed at Jerusalem. Joab struck Rabbah, and overthrew it.
These verses are parallel with 2Sam.  11:1,2 Samuel 12:26,30-31; and our comments on what is written here are on pages 135,163-166.  We might add here that this chapter marks a terrible turning point in David's life. Not only is there the matter of his torturing the Ammonites, but his adultery with Bathsheba, and his heartless murder of Uriah the Hittite and seventeen of his fellow-soldiers in a vain effort to hide his sin - all took place in connection with this siege of Rabbah.  The bad days of David's life began right here.