So, then, whatever may have been the immediate horizon of the prophet, and though, there may have stood on it some historical event, the city which he sees falling is other than any material Babylon, and the strong city in which he rejoices is other than the material Jerusalem, though it may have suggested the metaphor of my text. The song fits our lips quite as closely as it did the lips from which it first sprang, thrilling with triumph: 'We have a strong city; salvation will God appoint for walls and bulwarks. Open ye the gates, that the righteous nation which keepeth the truth may enter in.' There are three things, then, here: the city, its defences, its citizens. I. The City. Now, no doubt the prophet was thinking of the literal Jerusalem; but the city is ideal, as is shown by the bulwarks which defend, and by the qualifications which permit entrance. And so we must pass beyond the literalities of Palestine, and, as I think, must not apply the symbol to any visible institution or organisation if we are to come to the depth and greatness of the meaning of these words. No church which is organised amongst men can be the New Testament representation of this strong city. And if the explanation is to be looked for in that direction at all, it can only be the invisible aggregate of ransomed souls which is regarded as being the Zion of the prophecy. But perhaps even that is too definite and hard. And we are rather to think of the unseen but existent order of things or polity to which men here on earth may belong, and which will one day, after shocks and convulsions that shatter all which is merely institutional and human, be manifested still more gloriously. The central thought that was moving in the prophet's mind is that of the indestructible vitality of the true Israel, and the order which it represented, of which Jerusalem on its rock was but to him a symbol. And thus for us the lesson is that, apart altogether from the existing and visible order of things in which we dwell, there is a polity to which we may belong, for 'ye are come unto Mount Zion, the city of the living God,' and that that order is indestructible. Convulsions come, every Babylon falls, all human institutions change and pass. 'The kingdoms old' are 'cast into another mould.' But persistent through them all, and at the last, high above them all, will stand the stable polity of Heaven, '_the_ city which hath _the_ foundations.'