Beware:
All too often,
We say
What we hear others say.
We think
What we’re told that we think.
We see
What we’re permitted to see.
Worse!
We see what we’re told that we see.
Repetition and pride are the keys to this.
To hear and to see
Even an obvious lie
Again
And again and again
May be to say it,
Almost by reflex
Then to defend it
Because we’ve said it
And at last to embrace it
Because we’ve defended it
And because we cannot admit
That we’ve embraced and defended
An obvious lie.

Thus, without thought,
Without intent,
We make
Mere echoes
Of ourselves —
And we say
What we hear others say.

Octavia Butler (1947-2006) American writer

Parable of the Talents, ch. 18, epigram (1998)
    (Source)

Internally cited to the book's scripture, Earthseed: The Books of the Living,, and to a poem, "Warrior," written by the protagonist's uncle, Marcos Duran.