Where are those too, who deny Him to be very God? We see here that He is called very Light. But if He lighteneth every man that cometh into the world, how is it that so many have gone on without light? For all have not known the worship of Christ. The answer is: He only enlighteneth every man, so far as pertains to Him. If men shut their eyes, and will not receive the rays of this light, their darkness arises not from the fault of the light, but from their own wickedness, inasmuch as they voluntarily deprive themselves of the gift of grace. For grace is poured out upon all; and they, who will not enjoy the gift, may impute it to their own blindness.
Reproduced in full. Translation: Oxford 1841 (Newman), public domain (Public domain).
Also cites: Hom. viii. c. 2