In what way does Okonkwo suggest going against the customs of the Igbo as an attempt to preserve the customs?

Okonkwo suggests war against the Christians. This is not a popular idean because many from the tribe are converts.... they would be fighting against their own people.

"The white man is very clever. He came quietly and peaceably with his religion. We were amused at his foolishness and allowed him to stay. Now he has won our brothers, and our clan can no longer act like one. He has put a knife on the things that held us together and we have fallen apart" (126-7).