Tractates on the Gospel of John

³ For, indeed, all men are lamps, since they can be both lighted and extinguished. Moreover, when the lamps are wise, they shine and glow with the Spirit; yet also, if they did burn and are put out, they even stink. The servants of God remain good lamps by the oil of His mercy, not by their own strength. The free grace of God, truly, is the oil of the lamps. “For I have labored more than they all,” says a certain lamp; and lest he should seem to burn by his own strength, he added, “But not I, but the grace of God that was with me.” All prophecy, therefore, before the coming of the Lord, is a lamp.

Of this lamp the Apostle Peter says: “We have a more sure word of prophecy, to which you do well giving heed, as unto a lamp shining in a dark place, until the day dawn, and the day-star arise in your hearts.” Accordingly the prophets are lamps, and all prophecy one great lamp. What of the apostles? Are not they, too, lamps? They are, clearly. He alone is not a lamp. For He is not lighted and put out; because “even as the Father has life in Himself, so has He given to the Son to have life in Himself.”

The apostles also, I say, are lamps; and they give thanks because they were both lighted by the light of truth, and are burning with the spirit of charity, and supplied with the oil of God's grace. If they were not lamps, the Lord would not say to them, “You are the light of the world.” For after He said, “You are the light of the world,” He shows that they should not think themselves such a light as that of which it is said, “That was the true light, that enlightens every man coming into this world.”

But this was said of the Lord at that time when He was distinguished from John (the Baptist). Of John the Baptist, indeed, it had been said, “He was not the light, but that he might bear witness of the light.” And lest you should say, How was he not the light, of whom Christ says that “he was a lamp”?— I answer, In comparison of the other light, he was not light. For “that was the true light that enlightens every man coming into this world.” Accordingly, when He said also to the disciples, “You are the light of the world,” lest they should imagine that anything was attributed to them which was to be understood of Christ alone, and thus the lamps should be extinguished by the wind of pride, when He had said, “You are the light of the world,” He immediately subjoined, “A city that is set on a hill cannot be hid; neither do men light a candle and put it under a bushel, but an a candlestick, that it may shine on all that are in the house.”

But what if He did not call the apostles the candle, but the lighters of the candle, which they were to put on a candlestick? Hear that He called themselves the candle. “So let your light shine,” says He, “before men, that they, seeing your good works, may glorify,” not you, but “your Father who is in heaven.”