What does 2 Samuel 11:1 mean?

And it came to pass, at the return of the year, at the time when kings go outto battle, that David sent Joab, and his servants with him, and all Israel; and they destroyed the children of Ammon, and besieged Rabbah. But David tarried at Jerusalem.

And it came to pass, after the year was expired, at the time when kings go forth to battle, that David sent Joab, and his servants with him, and all Israel; and they destroyed the children of Ammon, and besieged Rabbah. But David tarried still at Jerusalem.

And it came to pass, at the return of the year, at the time when kings go outto battle, that David sent Joab, and his servants with him, and all Israel; and they destroyed the children of Ammon, and besieged Rabbah. But David tarried at Jerusalem.

Now in the spring, at the time when kings go out to war, David sent Joab and his servants and all Israel with him; and they made waste the land of the children of Ammon, and took up their position before Rabbah, shutting it in. But David was still at Jerusalem.

And it cometh to pass, at the revolution of the year--at the time of the going out of the messengers--that David sendeth Joab, and his servants with him, and all Israel, and they destroy the Bene-Ammon, and lay siege against Rabbah. And David is dwelling in Jerusalem,

And it came to pass at the return of the year, at the time when kings go forth to war, that David sent Joab and his servants with him, and all Israel, and they spoiled the children of Ammon, and besieged Rabba: but David remained in Jerusalem.

And it came to pass, at the return of the year, at the time when kings go forth, that David sent Joab, and his servants with him, and all Israel; and they laid waste the [land of the] children of Ammon, and besieged Rabbah. But David abode at Jerusalem.