What is the most important message in "Things Fall Apart"?

The main message in the novel is that the Igbo are not the brutal savage tribesmen people believe them to be, but rather people who care about each other, live together, and have a strong community. That is most likely why the author wrote so much before the occupation, to show them in a sympathetic light, which the white missionaries are unable to see.

I think what it shows is the importance of listening to your culture and not abandaning the people you love and care about. Even though they exiled Okonkwo, 7 years later he came back to avenge his tribes beliefs because they were sacred to him.