What (besides news) does Obierika bring to Okonkwo? Why is this important to Okonkwo?

He brings two bags full of cowries; they are money he has made off of the yams Okonkwo left with him. Obierika comes with two young men as his attendants, and he and Okonkwo great each other joyfully. This brings a little validation to Okonkwo that he desperately needs. They eat kola with Uchendu, and Obierika shares a bit of disturbing news.