John Calvin on John 1:10

10. He was in the world. He accuses men of ingratitude, because of their own accord, as it were, they were so blinded, that the cause of the light which they enjoyed was unknown to them. This extends to every age of the world; for before Christ was manifested in the flesh, his power was everywhere displayed; and therefore those daily effects ought to correct the stupidity of men. What can be more unreasonable than to draw water from a running stream, and never to think of the fountain from which that stream flows? It follows that no proper excuse can be found for the ignorance of the world in not knowing Christ, before he was manifested in the flesh; for it arose from the indolence and wicked stupidity of those who had opportunities of seeing Him always present by his power. The whole may be summed up by saying, that never was Christ in such a manner absent from the world, but that men, aroused by his rays, ought to have raised their eyes towards him. Hence it follows, that the blame must be imputed to themselves.