Why does Achebe include a funeral ceremony at this point in a novel

Achebe includes a funeral at this point in the story to illustrate how things can happen by chance.... how a man can spend his whole life trying to improve himself, to take care of his family, to become more, and still lose everything in only a moment. Thus, the beginning of Okonkwo's tragedy is a complete accident. It is a moment of blind chance that drives Okonkwo from his homeland. The greatest loss is more than material: Okonkwo's faith in the power of hard work is shaken. His will and strong arm are unable to prevent this disaster. As a middle-aged man, Okonkwo is being forced to start over again.

Although the event is an accident, it should also be remembered that Ezeudu was the man who warned Okonkwo not to take hand in Ikemefuna's death. The disaster, a seeming accident, seems to confirm the fears of Obierika, who warned Okonkwo that the earth goddess did not smile on Okonkwo's participation in Ikemefuna's murder. However, the incident here is as literary as it is mystical; the calamity taking place at Ezeudu's funeral is a kind of poetic justice more than it is an example of divine retribution. It is one of many incidents in the novel where tribal ceremonies and rites resonate with the novel's central action.