Observe, it is not "Ye carry the light," but "Ye _are_ the light." We are apt to think of light in the abstract--as truth, as doctrine, as something to be believed and held and expounded. We quote the familiar words, "Great is the Truth, and it shall prevail," and we imagine they are true. They are true indeed, in the long run, but not as often understood, certainly not in the region of the moral and spiritual. Of course truth in the abstract, especially moral and spiritual truth, ought to prevail; but it never does when men's interests lie, or seem to lie, in the contrary direction. Such truth, to be mighty, must be vitalised; it must glow in human hearts, burn on human tongues, shine in human lives. The King of truth knew this well; and hence He placed the hope of the future, the hope of dispelling the world's darkness, not in abstract truth, but in truth incarnate in the true disciple: "_Ye_ are the light of the world." In the strictest and highest sense, of course, Christ Himself is the Light of the world. This is beautifully set forth in discourses reported by another Evangelist (John viii. 12, ix. 5); and, indeed, it has been already taught by implication in the Evangel before us, where, as we have seen, the opening of Christ's ministry is likened to sunrise in the land of Zebulon and Naphtali (chap. iv. 16). But the personal Christ cannot remain upon the earth. Only for a few years can He be in this way the Light of the world, as He expressly says in one of the passages above referred to (John ix. 5); and He is speaking now not for the next few years but for the coming centuries, during which He must be represented by His faithful disciples, appointed to be His witnesses (Acts i. 8) to the ends of the earth; so at once He puts the responsibility on them, and says, "Ye are the light of the world." This responsibility it was impossible to avoid. As a matter of course, the kingdom of heaven must be a prominent object in the sight of men. The mountain of the Lord's house must be established on the top of the mountains (Isa. ii. 2), and therefore may not be inconspicuous: "A city set on a hill cannot be hid." It has been often said, but it will bear repeating, that Christians are the world's Bible. People who never read a word of either Old or New Testament will read the lives of those who profess to draw their inspiration thence, and will judge accordingly. They will form their opinions of Christ and of His kingdom by those who call themselves or are called by others Christians. "A city set on a hill _cannot_ be hid." Here we have a truth complementary to that other conveyed in the symbol of salt. It taught that true Christians exert a great deal of silent, unobserved influence, as of salt hidden in a mass; but, besides this, there is their position as connected with the kingdom of heaven which forbids their being wholly hid.