How does the killing of Ikemefuna foreshadow the fall of Okonkwo in Things Fall Apart?

Ikemefuna had been placed in Okonkwo's care after it had
been decided that another village, Mbaino, had to offer up a young virgin and a young
boy as compensation for the killing of Ogbuefi Ujo's wife when she went to market there.
Ikemefuna, who was fifteen at the time, lived in Okonkwo's care for three years before
it was decided that he had to be executed.

Ezeudu had asked
Okonkwo not to be involved in Ikemefuna's execution, but when the men came to take
Ikemefuna, Okonkwo accompanied them. When they were far outside of the village, one of
the men struck Ikemefuna, but the blow did not kill him. Ikemefuna cried out, "My
father, they have killed me!" and Okonkwo, out of fear, struck him down.
He was afraid that the men would think him a coward if he did not do
so.

This fear is born out of
Okonkwo's pride. He always had to prove himself a man and his harsh
actions towards his family and others spoke volumes of what it meant for Okonkwo to be a
man.

It is in this sense then, that
Ikemefuna's killing foreshadows Okonkwo's fall, for it was this same fear, borne out of
pride, that led to Okonkwo killing the  court messenger who came to break up a meeting
in their village.

The gathering had been
called to discuss what kind of action was to be taken against the evil which had invaded
their society - this is, of course, a reference to the missionaries. Okonkwo had been a
the forefront of protest and they had burned down Enoch's compound and the church. The
village had to pay 250 bags of cowries for their men, Okonkwo included, to be released
from captivity.

After the messenger's killing, the
Commissioner and a band of soldiers came to arrest
Okonwo.

Here again, it was Okonkwo's pride
which drove him to suicide. Instead of succumbing to the will of the Commissioner and
his men, Okonkwo hanged himself, in spite of his action being deemed an abomination by
his clan, who would refuse to bury his body or even touch
it.