Origen on the way of antithesis

"By way of antithesis to sensible things, the scripture usually calls intelligible things spirit and spiritual." (Con. Cel. VI,70)

Origen on the epistemology of righteousness

”[...]if we want to know what righteousness is, it is essential for us to know what unrighteous is; and when we have arrived at a complete knowledge of unrighteousness, on that basis we shall recognize what righteousness is as well; for when it becomes clear what is unjust, as a consequence, what is just will become visible as well. And because righteousness is in God, whose nature is inaccessible to human perception, but unrighteousness dwells in us men, in fact in all rational creatures, from our unrighteousness, which is known to us, the righteousness of God, which is, as it were, inaccessible and incomprehensible to us, is recognized and confirmed and produced as if from the opposition of opposites.” (In Rom. 3.1.7)