1 Chronicles 20:1-2

1In the spring of the year, the time when kings go out to battle, Joab led out the army and ravaged the country of the Ammonites and came and besieged Rabbah. But David remained at Jerusalem. And Joab struck down Rabbah and overthrew it.

2And David took the crown of their king from his head. He found that it weighed a talent of gold, and in it was a precious stone. And it was placed on David's head. And he brought out the spoil of the city, a very great amount.