Proverbs 17:22 (ESV)
A joyful heart is good medicine,
but a crushed spirit dries up the bones.
Because of a heart attack a couple of years ago, I am on a regiment of medication. Every week my wife lays out pills in piles and I dutifully take them morning and night. When I had the heart attack there was plenty of speculation as to the cause. Along with food habits and no habit of excercise, most of the advice I received was that I had to slow down and figure out how to reduce my stress levels. If I would have followed the medical "advice" of the above verse I probably wouldn't have to take the meds today. Putting yourself under stress is one sure way to "dry up the bones." This contrasting parallelism give us the wisdom that trusting in God (the real source of joy) is good medicine, while living without joy will dry the bones. The best medicine is to be controlled by the Spirit. The fruit of the Spirit is love, "joy", etc. A joyful heart comes from the fear of the Lord and trusting in Him and allowing the Spirit to rule. Without it you are under stress with dried up bones that produces a broken spirit and ... eventually a broken heart. We don't muster-up a joyful heart. We don't wait for circumstances to produce a moment of happenstance. Happy is a word that comes from a root word, "hap," which means something just "happened" to produce the moment. People get happy because some particular circumstance changed to their favor. Happiness is not a joyfulness. A joyful heart comes from allowing the Spirit of God to work within us, based upon the truth of God, sharpening us into a deeper knowledge of and shape like Christ. That is great medicine. I will take heart meds the rest of my life for the way I lived without Christlike joy. One of the "pills" I take every day, now, is to allow the Spirit of God to shape my life. He is good medicine for a guilty and shameful soul.