We were supposed to be better. It is what we've always told ourselves -- Wakanda the Unconquered. Wakanda The Advanced. Wakanda The Exceptional.
-- Changamire (chapter 9)

Importance: Changamire is is lamenting to his wife his fear that Wakanda may not actually be the great nation he has always believed it way. This shows the reader the depressed state T'Challa must bring Changamire back from in order to help defeat The People.

Hope be the hilt, and rage be the blade. Now they are joined. Behold, Tetu, the sword of The People unsheathed.
-- Zenzi (chapter 9)

Importance: Zenzi speaks this as she uses her powers to amplify the emotions of their soldiers. It is pivotal in signaling the final battle between The People and the Wakandan government is fast approaching.

I confess it: Wakanda cannot resist the combined might of Alkama and the Jabari-Lands at once. The Golden City will fall. But it will not alone.
-- Shuri (chapter 10)

Importance: Shuri is speaking...