To the prophecies of gospel grace very fitly is a song annexed, in which we may give God the glory and take to ourselves the comfort of that grace: In that day, the gospel day, which the day of the victories and enlargements of the Old Testament church was typical of (to some of which perhaps this has a primary reference), in that day this song shall be sung; there shall be persons to sing it, and cause and hearts to sing it; it shall be sung in the land of Judah, which was a figure of the gospel church; for the gospel covenant is said to be made with the house of Judah, Heb 8:8. Glorious things are here said of the church of God.

I.That it is strongly fortified against those that are bad (Isa 26:1): We have a strong city. It is a city incorporated by the charter of the everlasting covenant, fitted for the reception of all that are made free by that charter, for their employment and entertainment; it is a strong city, as Jerusalem was, while it was a city compact together, and had God himself a wall of fire round about it, so strong that none would have believed that an enemy could ever enter into the gates of Jerusalem, Lam 4:12. The church is a strong city, for it has walls and bulwarks, or counterscarps, and those of God's own appointing; for he has, in his promise, appointed salvation itself to be its defence. Those that are designed for salvation will find that to be their protection, Pe1 1:4.

II.That it is richly replenished with those that are good, and they are instead of fortifications to it; for the inhabitants of Jerusalem, if they are such as they should be, are its strength, Zac 12:5. The gates are here ordered to be opened, that the righteous nation, which keeps the truth, may enter in, Isa 26:2. They had been banished and driven out by the iniquity of the former times, but now the laws that were made against them are repealed, and they have liberty to enter in again. Or, There is an act for a general naturalization of all the righteous, whatever nation they are of, encouraging them to come and settle in Jerusalem. When God has done great things for any place or people he expects that thus they should render according to the benefit done unto them; they should be kind to his people, and take them under their protection and into their bosom. Note, 1. It is the character of righteous men that they keep the truths of God, a firm belief of which will have a commanding influence upon the regularity of the whole conversation. Good principles fixed in the head will produce good resolutions in the heart and good practices in the life. 2. It is the interest of states to countenance such, and court them among them, for they bring a blessing with them.

III.That all who belong to it are safe and easy, and have a holy security and serenity of mind in the assurance of God's favour. 1. This is here the matter of a promise (Isa 26:3): Thou wilt keep him in peace, peace, in perfect peace, inward peace, outward peace, peace with God, peace of conscience, peace at all times, under all events; this peace shall he be put into, and kept in the possession of, whose mind is stayed upon God, because it trusts in him. It is the character of every good man that he trusts in God, puts himself under his guidance and government, and depends upon him that it shall be greatly to his advantage to do so. Those that trust in God must have their minds stayed upon him, must trust him at all times, under all events, must firmly and faithfully adhere to him, with an entire satisfaction in him; and such as do so God will keep in perpetual peace, and that peace shall keep them. When evil tidings are abroad those shall calmly expect the event, and not be disturbed by frightful apprehensions arising from them, whose hearts are fixed, trusting in the Lord, Psa 112:7. 2. It is the matter of a precept (Isa 26:4): "Let us make ourselves easy by trusting in the Lord for ever; since God has promised peace to those that stay themselves upon him, let us not lose the benefit of that promise, but repose an entire confidence in him. Trust in him for ever, at all times, when you have nothing else to trust to; trust in him for that peace, that portion, which will be for ever." Whatever we trust to the world for, it will be but for a moment: all we expect from it is confined within the limits of time. But what we trust in God for will last as long as we shall last. For in the Lord Jehovah-Jah, Jehovah, in him who was, and is, and is to come, there is a rock of ages, a firm and lasting foundation for faith and hope to build upon; and the house built on that rock will stand in a storm. Those that trust in God shall not only find in him, but receive from him, everlasting strength, strength that will carry them to everlasting life, to that blessedness which is for ever; and therefore let them trust in him for ever, and never cast away nor change their confidence.

In that day shall this song be sung in the land of Judah,.... When great things shall be done: for the church and people of God; and when antichrist and all their enemies are destroyed, as mentioned in the preceding chapter Isa 25:1; then this song shall be sung expressed in this throughout; which the Targum calls a "new" song, an excellent one, as the matter of it shows; and which will be sung in the land of Judah, the land of praise in the congregation of the saints, the professors and confessors of the name of Jesus: in Mount Zion, 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.