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.

He came to His own, and His own people did not receive Him. 

Here the Evangelist, obviously, speaks of the Economy of salvation in the flesh, and the whole order of thought is as follows: The Light was true in the world, without the flesh and was not known, then it came to His own with the flesh. By "his own" you can understand to Him either the whole world, or Judea, which He has chosen, as a portion of the inheritance, as a plot and His property (Psalm 113:2). "And His own did not receive Him," or the Jews, or other people created by Him. In this way he mourns the madness of people and is amazed at the love for mankind of the Lord. Being His own, he says, not all accepted Him, for the Lord does not attract anyone by force, but leaves them to His own discretion and arbitrariness.

 And to those who received Him, to those who believe in His name, He gave the power to become children of God.