Two Kinds of Sight.
I. It is the striking contrast in these words to which I would draw your attention, the wonderful difference between the real state and the fancied state, and more especially to one word which is the key to the whole: that sin is blind: blind in a world of beauty and light; blind in a region of pitfalls, and delusions, and death. But mark for this is what makes it so fearful it is the blindness of the madman, who feels sure that he sees better than the sane. There are two powers of sight, the one real and the other unreal, and if we judge with sinful eyes, we never see reality. The faculty is wanting, and we do not, cannot, know the want unless we believe humbly. No keenness of the natural, intellectual eye matters at all, as a telescope does not make a man a better judge of colours. We may boast and argue from the piercing powers of sight, which can at the distance of millions of miles discover hidden worlds. A telescope is mere intellectual knowledge, and the eyes of the mere intellectual man are set in this distant focus; and the power of seeing the glory and beauty of the earth on which he lives and things around him is not his, however much he boasts of his sight.
II. Sin is blindness, and this sight is a new power. The truth of God cannot be seen by any unholy eye; and to pass through life trusting to our own judgments is to trust to a telescope to distinguish colours, to a microscope to show us stars, to feet for flying, or any incongruous mixture of wrong powers and functions. Holy Scripture expressly tells us, what all experience confirms, that spiritual things are folly to the natural man, for the simple reason that he does not see them, and so scorns them, just as a clever savage might despise electricity. Sin is blind. The pure see God, and there is no truth which is not of God. No impure spirit ever sees truth.
E. Thring, Uppingham Sermons,vol. i., p. 5.
References: Revelation 3:18. Homiletic Quarterly,vol. i., p. 404.Revelation 3:19. Spurgeon, Sermons,vol. iii., No. 164; Ibid., Evening by Evening,p. 159.