This one, he says, was sent from God to bear witness to the light. Then, lest anyone should think that his testimony was truly necessary for the Only-begotten, as if in need of something, the Evangelist adds that John came to bear witness to the Son of God, not because He needed His testimony, but so that all would believe through Him. Did all also believe through him? No. How then does the Evangelist say: that all may believe? How? - as much as depended on him, he testified in order to attract everyone, and if some did not believe, then he does not deserve blame. And then the sun rises to illuminate everyone, but if someone shuts himself up in a dark room and does not use its ray, then is the sun to blame for this? So it is here. John was sent that all might believe through him; if this does not happen, he is not to blame.

He was not the light, but was sent to bear witness to the Light.

 Since it often happens that the witness is higher than the one about whom he testifies, so that you do not think that John, who testifies to Christ, was higher than Him, the Evangelist, in refutation of this evil thought, says: "He was not light." But perhaps someone will say: Can we not call John, or any other of the saints, light? We can call each of the saints Light, but we cannot call Light, in this sense. For example, if someone says to you, "Is John light?" -Admit it. But if he asks thus: Is John this Light, say: No. For he himself is not light in the proper sense, but light by communion, which has radiance from the true light.

There was the true Light, which enlightens every person who comes into the world. 

The Evangelist intends to speak of the Economy of the Only-begotten in the flesh, that He came to His own, that He became flesh. And so, lest anyone should think that He did not exist before the Incarnation, for this purpose He raises thought to being before any beginning and says that the true Light was also before the Incarnation. By this he overthrows both the heresy of Photinus and Paul of Samosata, who asserted that the Only-begotten then received existence when He was born of the Virgin, and did not exist before. And you, Arian, who do not recognize the Son of God as the true God, listen to what the Evangelist says: "The true light." And you, Manichaeans, who say that we were created by an evil creator, hear that the true Light enlightens every man. If the evil creator is darkness, then he cannot enlighten anyone. Therefore, we are creatures of true Light. And how, some will say, enlightens every man, when we see some darkened? As much as depends on Himself, He enlightens everyone. For tell me, perhaps, are we not all intelligent? Do we not all by nature know good and what is contrary to it? Do we not have the ability to know the Creator through meditation on creatures? Wherefore reason, which is given to us and instructs us by nature, which is called the law of nature, may be called the light given to us by God. But if some have made bad use of reason, they have darkened themselves. Others resolve this objection in the following way: they say, the Lord enlightens every person who comes "into the world" (in Greek, adornment, order), that is, into a better state, and tries to adorn his soul, and not leave it disorderly and ugly.

     He was in the world, and the world was made through Him, and the world did not know Him. 

He was in the world as the omnipresent God, and one can say that he was in the world in relation to industry and preservation. Yet he says, Why do I say that I was in the world, when there would have been no world, if He had not created it? From all sides He proves that He is the Creator, at the same time dismissing the madness of Manes, who said that the evil Creator produced everything, and the madness of Arius, who called the Son of God a creature, and at the same time every man, leading to the confession of the Creator, teaching not to serve creatures, but to worship the Creator. But "the world," he says, "has not known Him," that is, bad people who have taken up worldly affairs. For the name "world" also signifies this universe, as it is said here: "the world was made through Him"; it also means those who philosophize according to worldly things, as it is said here: "the world has not known Him", that is, people who are attached to the earth. But all the saints and prophets have known.