Uriah was noble

“In the morning David wrote a letter to Joab and sent it with Uriah. In it he wrote, ‘Put Uriah in the front line where the fighting is fiercest. Then withdraw from him so he will be struck down and die.’” 2 Samuel 11:14-15
2 Samuel 11 gives us the story of David’s sin with Bathsheba – the event that would define his life from that point onward (for example, see 1 Kin. 15:5). David tried all kinds of ways to cover up the sin. He called for Uriah to be brought home from the battlefield to Jerusalem, thinking that after he had given David an account of the battle, he would go back to his house. Then, a few months later when his wife’s pregnancy started to show, nobody would think anything of it. But Uriah refused to go home, and instead spent the night at the palace. The next day, David tried again – this time getting Uriah drunk with wine. But he still did not go to his house. After this, David wrote a letter to Joab, telling him to put Uriah in a place where he would be killed in battle. And here’s the thing: he gave this letter to Uriah to be the messenger!
So Uriah carried his own death sentence back to Joab. He could have looked at the letter, and realised what was about to happen, and done something about it, but he was noble – more noble than David at this point. Everything Uriah did was above reproach. But instead of commending him, David found this an inconvenience. Also, Uriah was not the only one to be killed (2 Sam. 11:24). There were other innocent men, besides Uriah, who died because of David’s plan to cover up his sin. Indeed, this was the lowest point in David’s morality.