Isaiah 66:10

10.Rejoice ye with Jerusalem. He promises that they who formerly were sad and melancholy shall have a joyful condition; for Isaiah has in view not his own age, but the time of the captivity, during which believers continually groaned, and, overwhelmed with grief, almost despaired; and therefore he exhorts and stimulates to joy all believers, who are moved by strong affection toward the Church, and reckon nothing more desirable than her prosperity. In this way he instructs them that none shall have a share in so valuable a blessing but they who are prompted by a godly love of the Church, and desire to seek her deliverance, and that too when she is contemptible in the eyes of the world; as the Psalmist says,

“For thy meek ones love her stones, and will have compassion on her dust.”
(Psalms 102:14.)

And therefore he adds, —

All ye that mourn for her; for, since in the captivity there was frightful and shocking desolation, and there appeared to be no longer any hope of safety, he arouses believers, and bids them be of good cheer, or at least prepare themselves for joy. And this exhortation contains also a promise and something more, for a bare promise would not have carried so much weight. But those statements must not be limited exclusively to a single period; for we ought to abide by the general rule, of which we have often spoken already, namely, that those promises must be extended from the return of the people down to the reign of Christ, and to the full perfection of that reign.