Adam Clarke on John 12:46

I am come a light into the world - Probably referring to what his forerunner had said, Joh 1:5. Before the coming of this Savior, this sun of righteousness, into the world, all was darkness: at his rising the darkness is dispersed; but it only profits those whose eyes are open to receive the rays of this sun of righteousness. See on Joh 1:5 (note); Joh 3:19 (note); Joh 8:12 (note); Joh 9:5 (note).