'Salvation will God appoint for walls and bulwarks,' and if we realise, as we ought to do, His purpose to keep us safe, and His power to keep us safe, and the actual operation of His hand keeping us safe at every moment, we shall not ask that these defences shall be supplemented by the poor feeble earthworks that sense can throw up. III. Lastly, note the citizens. Our text is part of a 'song,' and is not to be interpreted in the cold-blooded fashion that might suit prose. A voice, coming from whom we know not, breaks in upon the first strain with a command, addressed to whom we know not--'Open ye the gates'--the city thus far being supposed to be empty--'that the righteous nation which keepeth the truth may enter in.' The central idea there is just this, 'Thy people shall be all righteous.' The one qualification for entrance into the city is absolute purity. Now, brethren, that is true in regard to our present imperfect denizenship within the city; and it is true in regard to men's passing into it in its perfect and final form. As to the former, there is nothing that you Christian people need more to have dinned into you than this, that your continuance in the state of a redeemed man, with all the security and blessing that attach thereto, depends upon your continuing to be righteous. Every sin, every flaw, every dropping beneath our own standard in conscience of what we ought to be, has for its inevitable result that we are robbed for the time being of consciousness of the walls of the city being about us and of our being citizens thereof. 'Who shall ascend into the hill of the Lord? And who shall stand in His holy place?' The New Testament, as emphatically as the old psalm, answers,' He that hath clean hands and a pure heart.' 'Let no man deceive you. He that doeth righteousness is righteous.' There is no way by which Christian men here on earth can pass into and keep within the city of the living God, except they possess personal purity, righteousness of life, and cleanness of heart. They used to say that Venice glass was so made that any poison poured into it shivered the vessel. Any drop of sin poured into your cup of communion with God, shatters the cup and spills the wine. Whosoever thinks himself a citizen of that great city, if he falls into transgression, and soils the cleanness of his hands, and ruffles the calm of his pure heart by self-willed sinfulness, will wake to find himself not within the battlements, but lying wounded, robbed, solitary, in the pitiless desert. My brother, it is 'the righteous nation' that 'enters in,' even here on earth.