the church of God below, Psa 149:1 , we have a strong city; not an earthly one, as Jerusalem; so the Jewish writers, Jarchi, Aben Ezra, and Kimchi, interpret it; nor the heavenly city, which God has prepared and built, and saints are looking for, and are citizens of: but rather the holy city, the New Jerusalem, described in Rev 21:2 or however, the church of Christ, as in the latter day; which will be a "strong" one, being of the Lord's founding, establishing, keeping, and defending; and whose strength will greatly lie in the presence of God, and his protection of it; in the number of its citizens, which will be many, when Jews and Gentiles are converted; and in their union one with another, and the steadfastness of their faith in Christ; when a "small one", as the church is now, shall become a "strong nation", Isa 60:22 , salvation will God appoint for walls and bulwarks; instead of walls, ditches, parapets, counterscarps, and such like fortifications; what they are to cities, that is salvation to the church and people of God; it is their safety and security: as God the Father is concerned in it, it flows from his love, which is unchangeable; it is by an appointment of his, which is unalterable; is secured by election grace, which stands not upon the works of men, but the will of God; and by the covenant of grace, ordered in all things, and sure; and by his power the saints are kept unto it: as Christ is concerned in it, it is as walls and bulwarks; he is the author of it, has completely finished it, and has overcome and destroyed all enemies; his righteousness is a security from all charges and condemnation; his satisfaction a bulwark against the damning power of sin, the curses of the law, and the wrath of God; his mediation and intercession are a protection of saints; and his almighty power a guard about them. As the Spirit is concerned in it, who is the applier of it, and evidences interest in it; it is a bulwark against sin, against Satan's temptations, against a spirit of bondage to fear, against error, and a final and total falling away; particularly the church's "walls" will be "salvation", and her "gates" praise, of which in the next verse Isa 26:2 , in the latter day glory; to which this song refers; see Isa 60:18 .