Proverbs 17:22, A merry heart doeth good like a medicine; but a broken spirit drieth the bones.
Similar to Proverbs 15:13, A merry heart maketh a cheerful countenance: but by sorrow of the heart the spirit is broken.
Another similar verse, Proverbs 15:15, All the days of the afflicted are evil: but he that is of a merry heart hath a continual feast.
These verses say that a merry heart is something to desire.
It has great value.
Not false merriment, psychology induced merriment, alcohol induced merriment, merriment from the pleasures of sin for a season.
All these are temporal and depend on circumstances.
We need merriment that depends on God. That is eternal.
Christians need to remember that to rejoice is our duty, our privilege, and an ornament to our profession in Christ. "A man's wisdom maketh his face to shine"
The kingdom of God is not a kingdom of darkness, but of righteousness, and peace, and joy in the Holy Spirit.