12. I am the light of the world. Those who leave out the former narrative, which relates to the adulteress, ³ connect this discourse of Christ with the sermon which he delivered on the last day of the assembly. It is a beautiful commendation of Christ, when he is called the light of the world; for, since we are all blind by nature, a remedy is offered, by which we may be freed and rescued from darkness and made partakers of the true light. Nor is it only to one person or to another that this benefit is offered, for Christ declares that he is the light of the whole world; for by this universal statement he intended to remove the distinction, not only between Jews and Gentiles, but between the learned and ignorant, between persons of distinction and the common people.

But we must first ascertain what necessity there is for seeking this light; for men will never present themselves to Christ to be illuminated, until they have known both that this world is darkness, and that they themselves are altogether blind. Let us therefore know that, when the manner of obtaining this light is pointed out to us in Christ, we are all condemned for blindness, and everything else which we consider to be light is compared to darkness, and to a very dark night. For Christ does not speak of it as what belongs to him in common with others, but claims it as being peculiarly his own. Hence it follows, that out of Christ there is not even a spark of true light. There may be some appearance of brightness, but it resembles lightning, which only dazzles the eyes. It must also be observed, that the power and office of illuminating is not confined to the personal presence of Christ; for though he is far removed from us with respect to his body, yet he daily sheds his light upon us, by the doctrine of the Gospel, and by the secret power of his Spirit. Yet we have not a full definition of this light, unless we learn that we are illuminated by the Gospel and by the Spirit of Christ, that we may know that the fountain of all knowledge and wisdom is hidden in him.

He who followeth me. To the doctrine he adds an exhortation, which he immediately afterwards confirms by a promise. For when we learn that all who allow themselves to be governed by Christ are out of danger of going astray, we ought to be excited to follow him, and, indeed, by stretching out his hand -- as it were -- he draws us to him. We ought also to be powerfully affected by so large and magnificent a promise, that they who shall direct their eyes to Christ are certain that, even in the midst of darkness, they will be preserved from going astray; and that not only for a short period, but until they have finished their course. For that is the meaning of the words used in the future tense, he shall not walk in darkness, but shall have the light of life. Such is also the import of this latter clause, in which the perpetuity of life is stated in express terms. We ought not to fear, therefore, lest it leave us in the middle of the journey, for it conducts us even to life. The genitive of life, in accordance with the Hebrew idiom, is employed, instead of the adjective, to denote the effect; as if he had said, the life-giving light. We need not wonder that such gross darkness of errors and superstitions prevails in the world, in which there are so few that have their eyes fixed on Christ.

13. The Pharisees therefore said. They adduce as an objection what is commonly said, that no man ought to be trusted, when speaking in his own cause. For a true testimony is put for "what is lawful and worthy of credit." In short, they mean that it is of no use for him to speak, unless he bring proof from some other quarter.

14. Though I testify concerning myself. Christ replies, that his testimony possesses sufficient credit and authority, because he is not a private person belonging to the great body of men, but holds a very different station. For when he says, that he knoweth whence he came, and whither he goeth, he thus excludes himself from the ordinary rank of men. The meaning therefore is, that every man is heard with suspicion in his own cause, and it is provided by the laws, that no man shall be believed, when he speaks for his own advantage. But this does not apply to the Son of God, who holds a rank above the whole world; for he is not reckoned as belonging to the rank of men, but has received from his Father this privilege, to reduce all men to obedience to him by a single word.

I know whence I came. By these words he declares that his origin is not from the world, but that he proceeded from God, and therefore that it would be unjust and unreasonable that his doctrine, which is Divine, should be subjected to the laws of men. But as he was at that time clothed with the form of a servant, in consequence of which they despised him on account of the mean condition of the flesh, he sends them away to the future glory of his resurrection, from which his Divinity, formerly hidden and unknown, received a clear demonstration. That intermediate condition, therefore, ought not to have prevented the Jews from submitting to God's only ambassador, who had been formerly promised to them in the Law.

But you know not whence I came, and whither I go. He means that his glory is not at all diminished by their unbelief. Again, as he has given the same testimony to us, our faith ought to despise all the reports and slanders of wicked men; for it cannot be founded upon God without rising far above the loftiest pride of the world. But in order that we may perceive the majesty of his Gospel, we ought always to direct our eyes to the heavenly glory of the Son of God, ⁴ and to hear him speaking in the world, so as to remember whence he came, and what authority he now possesses, after having discharged his embassy. For as he humbled himself for a time, so now he is highly exalted ⁵ at the right hand of the Father, that every knee may bow to him, (Philippians 2:10.)