What are quotes from Okonkwo that give readers insight into his personality in Things Fall Apart?

Chinua Achebe's Things Fall Apart centers on the strong traditional warrior Okonkwo as he adjusts to an evolving Umuofian landscape. Though Okonkwo is a man of relatively few words, the novel contains some key quotes that enable readers to get a better sense of the man who drives Achebe's classic tale. One notable quote occurs early in the text when Okonkwo asks Nwakibie for yams in a difficult harvest year:

I know what it is to ask a man to trust another with his yams, especially these days when young men are afraid of hard work. I am not afraid of work. . . I began to fend for myself at an age when most people still suck at their mothers' breasts. If you give me some yam seeds I shall not fail you (21).

Here, Okonkwo succinctly lays out the kind of man that he is. He is driven to succeed; he has had to work harder than many of his colleagues because his father's laziness held his family in poverty. This is an admirable trait that Okonkwo shows.
Okonkwo's intense fear of failure and being perceived as weak and "feminine" dominates his life. He works hard because he fears becoming his father. He defines masculinity in a toxic, rigid way. Indeed, his fear of being perceived as weak causes him to murder his adoptive son Ikemefuna. Okonkwo later questions why he is so shaken by his actions:

When did you become a shivering old woman. . . you, who are known in all the nine villages for your valor in war? How can a man who has killed five men in battle fall to pieces because he has added a boy to their number? Okonkwo, you have become a woman indeed (65).

These two quotes give readers piercing insight into Okonkwo as a character. His words allow us to see what he values and how his values are a double-edged sword.