John Gill Commentary Isaiah 26:15

"Thou hast increased the nation, O Jehovah, thou hast increased the nation; thou art glorified; thou hast enlarged all the borders of the land." — Isaiah 26:15 (ASV)

You have increased the nation, O Lord, you have
increased the nation
The righteous nation, (Isaiah 26:2) the church of God, by the numerous conversions of Jews and Gentiles; when the nation of the Jews shall be born at once, and the fulness and forces of the Gentiles are brought in; when the kingdoms of this world will become the kingdoms of our Lord, and of his Christ: this increase is repeated, to denote the certainty of it, and because a matter of great moment and importance:

you are glorified ;
as by the destruction of the antichristian powers, so by the enlargement of the church and kingdom of Christ; for now will the voices be heard in heaven, giving praise and glory to God: even those that are frightened with his judgments, as well as those that are affected with his goodness, will give glory to the God of heaven, (Revelation 11:13Revelation 11:17) (19:1-6) :

you had removed [it] far [unto] all the ends of the earth :
not the Jewish people now scattered throughout the world, but the righteous nation increased and enlarged, which now will be spread to the ends of the world; for Christ's kingdom will be from sea to sea, and from the river to the ends of the earth, (Psalms 72:8)

it may be rendered, "you have removed afar off all the ends of the earth": so De Dieu, who interprets it of the great men of the earth, the excellent in it, the cornerstones of it; but perhaps it may be better to understand hereby every island and mountain fleeing away at the destruction of antichrist, and the enlargement of Christ's kingdom, (Revelation 16:20) .