Numbers have no history. Numbers have no characters, have no reason to fight. Numbers are lost into the pool of the collective. Bereft of names, the victims ceased to be human. It was that much easier for the Nazis to incinerate them because they were burning numbers, not people.
Names carry humanity.
Names in our tradition are very important. They play an important role. The Torah reading that we are beginning this week which has its name from the first portion is also the same name as the book. And, indeed, a telling legend from our rabbis is the fact that they believe one of the reasons our ancestors merited liberation from bondage was the fact that they did not change their Hebrew names in Egypt. By maintaining their Hebrew names, they maintained their Jewish identity.