Answer:
Obierika represents a foil to the character of Okonkwo, his own best friend. And through the two men, we see both sides of the story and also presents a critical voice for the character of Okonkwo and his strict belief in his tradition and customs.
Step-by-step explanation:
The character of Obierika in Chinua Achebe's Things Fall Apart is presented as a contrast to the character of Okonkwo. The main theme of community, belonging, and tradition revolves around the whole story while also dealing with the emergence of the British in the African nation in an attempt to "civilize" them.
Though the two characters are close friends, they seem to at times be at loggerheads. At the time of the 'sacrifice' of the adopted son Ikemefuna in chapter 8, Obierika did not go along with the others for which Okonkwo is angry with him. But his best friend told him "If I were you, I would have stayed at home. What you have done will not please the earth. It is the kind of action for which the goddess wipes out whole families".
Again, in Chapter 20 when the missionaries came to their village during Okonkwo's exile, Obierika also seemed to disagree with this intrusion. But unlike Okonkwo who acts impulsively, Obierika thinks before he actually does things. And it is such that when Okonkwo vehemently opposes the missionaries and their 'supposed claims of bringing change' to the people, Obierika did not disagree like his friend. he did not accept the foreigners' move but he also did not act rashly either. And when he questioned the rise of the White man's power in his village, Obierika calmly explained to him the events of the period he was exiled. The accepting manner in which Obierika tells him about how the White man said "our customs are bad; and our own brothers who have taken up his religion also says that our customs are bad" shows his resignation in trying to oppose the influx of the new people and change.