What is the importance of the Croatian papers in Book II of the novel, The Woman Who Lost Her Soul?

In Book II, Marija and Stjepan are given some papers by the man helping them escape. Those papers are taken by a second man, whom the first man had trusted. Their absence triggers brutal beatings for Marija and Stjepan, which in turn provokes bitter, violent resentment on both their parts to those who failed to help and/or save them.