I. Let us endeavour to arrive at some distinct meaning of that remarkable expression doing truth. (1) The first thing in it is to be really in earnest. Until a man is thoroughly in earnest about his soul God will have nothing to do with him. But as soon as a man is really in earnest, the work is almost half done; at all events, the result is safe. (2) A man who is doing truth has begun to draw to Christ. He makes much of Christ. He begins to feel the power and beauty of Christ. He is learning to depend upon Christ; to find Christ in everything. (3) To do truth is to be very practical in religion. It is not only to hold Christ; but to carry out Christ into daily life. It is true that actions are the results of feelings; but every one who would have lightened feelings must do actions. Whoever will do His will, he shall know of the doctrine.
II. Of this character God says he is coming to the light. For there are assimilations in moral truth, as there are in nature, and wherever there is an assimilation, there is an attraction. This man has some light, and therefore he is under the influence of light! Light draws him. There is a principle in him which must be always running up to the Fountain from which this principle sprang. This man who comes to the light is daily growing in the beautiful grace of transparency of character. The nearer he gets to the light, the more transparent he is. His whole being can now bear examination. He loves truth; he courts truth; he is truth. There is reality in that man. You may weigh his words; you may scrutinise his actions: for he is learning to walk as a child of light. Up and up towards the very Fountain of light he is daily travelling. He is not light, but he is coming to the light. In greater nearness to Jesus every day; in more constant communion with Him; with more of His presence; in more of His image; he is striving to live to Him. Christ is a centre around which he moves continually, in a closer and a closer circle, coming to the light! He to Christ; Christ to him. The affinity grows stronger and stronger.
J. Vaughan, Fifty Sermons,2nd series, p. 251.
References: John 3:23-36. Homiletic Magazine,vol. ix., p. 184 John 3:24. Ibid.,vol. xi., p. 235.John 3:29; John 3:30. J. Stoughton, Christian World Pulpit,vol. vi., p. 395.