The joy whereof he speaketh is a fruit of faith. For it cannot be but that so soon as we know that God will be favorable and merciful our minds shall be wrapt with incomparable joy, and such as doth far pass all understanding, (Philippians 4:7.)

And there was great joy - This joy arose:
(1) From the fact that so many persons, before sick and afflicted, were restored to health.
(2) from the conversion of individuals to Christ.
(3) from the mutual joy of "families" and "friends" that their friends were converted. The tendency of a revival of religion is thus to produce great joy.

There was great joy in that city - No wonder, when they heard such glorious truths, and were the subjects of such beneficent miracles.

And there was great joy in that city. Both on a spiritual account, for the good of their souls, through the preaching of Christ and his Gospel to them; and on a temporal account; for the good of their bodies, or their friends, being dispossessed of devils, and healed of their diseases.

great joy in that city--over the change wrought on it by the Gospel, as well as the cures which attested its divine character.