John Gill's  Exposition of the Bible 

2 Samuel 11:18

Then Joab sent and told David all the things concerning the war;

Then Joab sent,.... Messengers to David, as soon as Uriah was killed:

and told David all the things concerning the war; how the siege had been carried on; what success they had had, good or ill; what their advantages and disadvantages; what men they had lost, and especially in one sally of the enemy upon them, for the sake of which the express was sent.