Whatever be the introduction to the words, '_I am the Light of the world: he that followeth me shall not walk in darkness_,' we perceive at once that they are in harmony with all that we have been reading in St. John. But we ought also to perceive that they are not mere repetitions of the sentences in the opening of the Gospel, and in the third chapter. The Light of the world comes forth here detecting, indeed, and manifesting the darkness in each man, but with a promise and assurance that it will prove itself mightier than the darkness. The Word made flesh says to the man who sees nothing but mists all around him, 'I can bring you into the clear sunshine.' He says to the man whose breath is stifled, whose limbs have suffered as much from the atmosphere he has dwelt in as his eyes, 'I am the Light of Life'--that which illuminates, quickens. There is certainly a progress and an order in all our Lord's teachings, whether we can trace it or not. The words on the last day of the feast, which could not be fulfilled till Christ was glorified, seem to make the conversation upon which we are now entering necessary. We want to know how the Water of Life is connected with the Light of Life; we want to know whence the Light and the Life are both derived. The answer of the Pharisees to our Lord's words--'_Thou bearest record of thyself; thy record is not true_'--leads us on in this path of discovery. This answer was no doubt suggested by a recollection of that which He had said Himself at the former feast (John v. 31). They thought they were confuting Him out of His own mouth; for surely to call Himself the Light of the world was as great a pretension as to call Himself the Christ. Could His own testimony be accepted for one assertion more than for the other? It was an all-important inquiry. The more earnestly the Pharisees pursued it--the more determined they were not to be content with any half solution of it--the better. If they had been in earnest, they would have been compelled to ask themselves--'And what evidence _can_ we have that will satisfy us whether such a claim as this is well-founded or not? What _can_ convince us whether one who says he is our Light, and the Light of the world, is uttering the most profound truth, or the most portentous falsehood?' They would then have been driven to plain facts. They must have considered how the sun proves itself to be a light to any man, or a light to all men; and what comfort there would be in learning from books that that is the function which it ought to perform, the blessing which men ought to receive from it. They were not in earnest; they would not grapple with facts. Facts were for that cursed people which did not know the law. What had doctors to do with such common things as the sun? What had the sun to do with the letters which they copied out? Something, perhaps, with the letter of that 19th Psalm, which begins with the light in the firmament, and ends with the law that enlightens the heart.