26 When Bathsheba heard that her husband was killed, she mourned for him.
27 Then David fetched her, she became his wife and had a son. But God was displeased with what David had done.
A few more words about this episode
David sent Joab to destroy the Ammonites and besiege Rabbah. (11:1)
David is no longer leading his armies in battle. Now he sends Joab to do it for him.
Rabbah is called Amman today and is the capital of Jordan. It is 104 kilometers east of Jerusalem. So the trips that Uriah took between the war front and Jerusalem would have taken many days.
She was purified from her uncleanness (11:4)
A woman had to be purified after her period according to Leviticus 15:19-33. Since Bathsheba had gone through her purification after her period, David wouldn't be guilty of having sex with a menstruating woman. It also indicates that she would be more likely to conceive at this time.
Go home and wash your feet. (11:8)
David isn't really telling Uriah to wash his feet. He's suggesting that he go home an have sex with his wife. That way Uriah will appear to be the father of the child that Bathsheba has conceived.