Identity
One of the major themes in the film is that of identity. In particular we see this theme in Lawrence as he is a British citizen and soldier, but with a passion for the Arab people in order that they might be free. In his attempt to give the Arab's their freedom through uniting them in battle, Lawrence is himself creating an identity. Prior to being in the desert he was confined to a desk job where he wasn't able to grow beyond the four walls that surrounded him. In the midst of the desert, where nothing grows, Lawrence flourishes by becoming the bridge between the Arab people and the British. But as he continues on his journey we see his new found identity brings him to a point of having to take actions that are against his personal beliefs. Thus we see the price Lawrence pays in the midst of a war campaign.
Non-Violence
Lawrence struggles throughout his journey with the Arab people with his belief of non-violence. Though he is plunged into the midst of a war where men die Lawrence is placed in a situation where he must kill his own men and this is vastly different. When one of his soldiers is wounded during their campaign they cannot leave the man behind because if they do the opposing force will torture them. Lawrence then must kill his wounded because the opposition does not recognize the Arab tribes Lawrence is working with as a real enemy thus they don't have to follow the Geneva Convention rules. We first see Lawrence have to kill the man he rescued from the desert in order to keep the peace between the two tribes he is uniting for war. We see that though he does not want to kill that he chooses to do so for the greater good of what must be done. It is a bridge he crosses multiple times and even though he understands the "rules" that they are playing by it still causes him to cross a line he wishes not to step a foot upon.
Allegiance
Lawrence sets out as a British soldier seeking to unite the Arab people in order help England gain more control in the Arab world. But as Lawrence continues on his journey we see how close he becomes with the Arab men he goes to battle with. We see him symbolically change out of his British military uniform into garments given to him by Sherif welcoming him as one of their own. Lawrence even wears these garments to speak with the general and we see that he is completely out of place amongst the men of the British military. And yet when he is back in the desert he also appears to out of place which leads to his being beaten. What is most important to note is that Lawrence has an allegiance to both the British and the Arabs. In the end, though Lawrence has an allegiance to himself and what he believes is right. When he sees the true nature of the British military's intent to share the spoils of the Arab land he desires nothing to do with it, and in the field with his Arab friends he realizes he is not a military man as he knows he is an "any man" when it is made clear he would give up all of his secrets to the enemy. In the end, Lawrence doesn't know if he has any allegiance at all as he is incapable of being allegiant to himself.
