“All the days of the afflicted are evil: But he that is of a merry heart hath a continual feast.”
‭‭Proverbs‬ ‭15‬:‭15‬ ‭KJV‬‬

Having a merry heart does not equate comedy or drunkenness like the heathen might interpret, after all king Belshazzar was drunken and seemingly happy and that was the root of his destruction: Daniel 5:1-30
Same with Nabal: 1 Samuel 25:36-38
Your merry heart should be an expression of your dependence on the word- you remain happy and joyful because of your great God and his extravagant grace so lavished on you, placing his joy in your spirit so even if everyone around you and everything external looks bleak, inside, you are full of joy; and nothing can take or change it. Only the word stirs joy within:
“These things have I spoken unto you, that my joy might remain in you, and that your joy might be full.”‭‭John‬ ‭15‬:‭11‬

Bible Reading Plan: Isahiah 52 and 2 chronicles 7