A shared theme through Steven Spielberg's "Saving Private Ryan" and "Schindler's List" could be the sacrifices made for a greater good. In "Saving Private Ryan," the company commander, Captain Miller, leads a squad of soldiers on a mission to locate the last surviving brother from a family back in the United States. While self-sacrifice isn't the goal of the protagonists in this film and, in fact, an argument ensues following the death of the medic regarding the sacrifices being demanded of these soldiers on behalf of another soldier, the ultimate sacrifice is made in the end, by the captain as well as most of the squad. Captain Miller's dying comment, "Earn this," uttered to Ryan, infuses the private with the sense of gratitude for the fact that, intended or not, lives were lost so that his could be spared.
Similarly, Oskar Schindler does not sacrifice his life so that the Jews under his care can survive, but he does sacrifice everything else. And, it could logically be argued that the extraordinary efforts he made to save these people from the concentration camps could have easily come at the cost of his life. Instead, he survived, but all of the material wealth he had worked for, and worshipped, was lost. The end of the film -- prior to the present-day visit to Schindler's grave by the descendents of those he saved, as well as by some of the actual people -- depicts Schindler breaking down in remorse for not having sacrificed every last bit of personal wealth he still possessed, for example, his car.
The selflessness depicted in a higher cause could be considered a common theme between the two films.