John 1:8

"He was not that Light." Now if he did not introduce this as setting himself against this suspicion, then the expression is absolutely superfluous, and tautology rather than elucidation of his teaching. For why, after having said that he "was sent to bear witness of that Light," does he again say, "He was not that Light"? (He says it,) not loosely or without reason; but, because, for the most part, among ourselves, the person witnessing is held to be greater, and generally more trustworthy than the person witnessed of; therefore, that none might suspect this in the case of John, at once from the very beginning he removes this evil suspicion, and having torn it up by the roots, shows who this is that bears witness, and who is He who is witnessed of, and what an interval there is between the witnessed of, and the bearer of witness.

Wherefore then did he come? "But that he might bear witness concerning the light." Why so? "That all might believe through him." And concerning what light was he to bear witness? "That was the true light." Wherefore is it added true? Because an enlightened man is also called a light; but the true light is that which enlightens. For even our eyes are called lights; and nevertheless, unless either during the night a lamp is lighted, or during the day the sun goes forth, these lights are open in vain. Thus, therefore, John was a light, but not the true light; because, if not enlightened, he would have been darkness; but, by enlightenment, he became a light. For unless he had been enlightened he would have been darkness, as all those once impious men, to whom, as believers, the apostle said, "Ye were sometimes darkness." But now, because they had believed, what? "but now are ye light," he says, "in the Lord." Unless he had added "in the Lord," we should not have understood. "Light," he says, "in the Lord:" darkness you were not in the Lord. "For ye were sometimes darkness," where he did not add in the Lord. Therefore, darkness in you, light in the Lord. And thus "he was not that light, but was sent to bear witness of the light."

John, a man of distinguished grace, was sent before Him, a man enlightened by Him who is the Light. For of John it is said, "He was not the Light, but that he should bear witness of the Light." He may himself be called a light indeed, and rightly so; but an enlightened, not an enlightening light. The light that enlightens, and that which is enlightened, are different things: for even our eyes are called lights, and yet when we open them in the dark, they do not see. But the light that enlightens is a light both from itself and for itself, and does not need another light for its shining; but all the rest need it, that they may shine.

But it will be said, that we do not allow John or any of the saints to be or ever to have been light. The difference is this: If we call any of the saints light, we put light without the article. So if asked whether John is light, without the article, thou mayest allow without hesitation that he is: if with the article, thou allow it not. For he is not very, original, light, but is only called so, on account of his partaking of the light, which cometh from the true Light.