A cheerful heart makes good medicine, but a crushed spirit dries up the bones.
Note, 1. It is healthful to be cheerful. The Lord is for the body, and has provided for it, not only meat, but medicine, and has here told us that the best medicine is a merry heart, not a heart addicted to vain, carnal, sensual mirth; Solomon himself said of that mirth, It is not medicine, but madness; it is not food, but poison; what doth it?
Pro 17:22 22 A joyful heart bringeth good recovery; And a broken spirit drieth the bones. The heart is the centre of the individual life, and the condition and the tone of the heart communicates itself to this life, even to its outermost circumference; the spirit is the power of self-consciousness which, according as it is lifted up or broken, also lifts up or breaks...
(Compare Pro 14:30; Pro 15:13). The effect of the mind on the body is well known. medicine--or, "body," which better corresponds with "bone." drieth--as if the marrow were exhausted.