Isaiah 65:18

But be ye glad and rejoice - (See the notes at Isaiah 51:11).

Forever - It is not to be momentary happiness - like a bright morning that is soon overcast with clouds. The joy of God’s people is to endure for ever, and they shall have ceaseless cause of praise and thanksgiving.

I create Jerusalem a rejoicing - A source of rejoicing; or a place of rejoicing.

And her people a joy - That is, in themselves joyful, and a source of joy to all others. The idea is, that the church would be a place of the highest happiness, and that they who were redeemed would have occasion of perpetual joy. The Saviour did not come to minister gloom, nor is the true effect of religion to make his people melancholy. Religion produces seriousness; but seriousness is not inconsistent with permanent happiness. Religion produces deep thought and soberness of deportment and conversation; but this is not inconsistent with a heart at ease, or with a good conscience, or with permanent joy. Religion fills the mind with hope of eternal life; and the highest happiness which the soul can know must be in connection with the prospect of unchanging blessedness beyond the grave.