What does "those whose palm-kernels were cracked by a benevolent spirit should not forget to be humble" mean?

In chapter four of Chinua Achebe’s Things Fall Apart, Okonkwo is told this by an elder after he calls a fellow clansman a woman after the clansman contradicts him at a village meeting. Okonkwo callously tells a man who has no titles, and is therefore an agbala, that the current meeting was for men only. Okonkwo is quickly chastised by his fellow clansmen and must apologize to the man.

This piece of advice...

In chapter four of Chinua Achebe’s Things Fall Apart, Okonkwo is told this by an elder after he calls a fellow clansman a woman after the clansman contradicts him at a village meeting. Okonkwo callously tells a man who has no titles, and is therefore an agbala, that the current meeting was for men only. Okonkwo is quickly chastised by his fellow clansmen and must apologize to the man.

This piece of advice essentially means that a man who has been lucky and afforded opportunities by the gods should not be overconfident about his position in society. Indeed, the elder is implying that Okonkwo has been given some lucky breaks by his gods that the agbala Osugo has not been afforded. His gods have granted him certain positive aspects of his life, or, in other words, cracked some palm-kernels for him. The elder warns Okonkwo against his prideful attitude, which ultimately contributes to Okonkwo’s tragic end. He reminds Okonkwo to remain humble and grateful for the things his gods have granted him, and to be empathetic to the plights of others, especially those from a lower social ranking who have not been given the same opportunities from the gods.