The saying appeals to common-sense. A man does not light a lamp and then smother it. The act of lighting implies the purpose of illumination, and, with everybody who acts logically, its sequel is to put the lamp on a stand, where it may be visible. All is part of the nightly routine of every Jewish household. Jesus had often watched it; and, commonplace as it is, it had mirrored to Him large truths. If our eyes were opened to the suggestions of common life, we should find in them many parables and reminders of high matters. Now this saying is a favourite and familiar one of our Lord, occurring four times in the Gospels. It is interesting to notice that He, too, like other teachers, had His favourite maxims, which He turned round in all sorts of ways, and presented as reflecting light at different angles and suggesting different thoughts. The four occurrences of the saying are these. In my text, and in the parallel in Luke's Gospel, it is appended to the Parable of the Sower, and forms the basis of the exhortation, 'Take heed how ye hear.' In another place in Luke's Gospel it is appended to our Lord's words about 'the sign of the prophet Jonah,' which is explained to be the resurrection of Jesus Christ, and it forms the basis of the exhortation to cultivate the single eye which is receptive of the light. In the Sermon on the Mount it is appended to the declaration that the disciples are the lights of the world, and forms the basis of the exhortation, 'Let your light so shine before men.' I have thought that it may be interesting and instructive if in this sermon we throw together these three applications of this one saying, and try to study the threefold lessons which it yields, and the weighty duties which it enforces. I. So, then, I have to ask you, first, to consider that we have a lesson as to the apparent obscurities of revelation and of our duty concerning them.