"Light," that is, the Word of God, shines "in darkness," that is, in death and error. For He, having submitted to death, so overcame it that He compelled it to vomit even those whom it had previously devoured. And in pagan error the preaching shines. "And the darkness did not overtake him." Neither death overcame Him, nor error. For this light, that is, the Word of God, is insurmountable. Some considered the flesh and earthly life to be "darkness." The Word shone even then, as it became in the flesh and was in this life, but darkness, that is, the opposite force, tempted and pursued the Light, but found Him invincible and invincible. The flesh is called darkness not because it is so by nature (let it not be!), but because of sin. For the flesh, as long as it is governed by the law of nature, has absolutely no evil, but when it moves beyond the limits of nature and serves sin, it becomes and is called darkness.

 There was a man sent from God, his name was John. 

Having told us about the pre-eternal existence of God the Word and intending to speak about the incarnation of the Word, the Evangelist inserts a speech about the Forerunner. And what else, if not about the birth of John the Baptist, can there be a word before the speech about the birth of the Lord in the flesh? The Evangelist says of the Forerunner that he was "sent" by God, that is, sent from God. For false prophets are not of God. When you hear that he was sent from God, then know that he did not say anything from himself or from people, but everything is from God. For this reason he is called an angel (Matt. 10:11; Mal. 3:1), and the advantage of an angel is not to say anything of himself. When you hear about an angel, do not think that John was an angel by nature, or that he came down from heaven; He is called an angel by deed and service. Since he preached and foretold the Lord, he was called an angel for this. For this reason the Evangelist, in refutation of the assumption of many, who perhaps thought that John was an angel by nature, says: "There was a man," sent from God.

 He came to bear witness, to bear witness to the Light, that all might believe through him. 

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.