2. Maintain habitual cheerfulness and tranquillity of mind. Few persons are aware of the influence which this has upon the health of the body.  If you are subject to melancholy, avoid it, and fight against it as a sin, dishonoring to God, and destructive of your own health and happiness.  It is dishonoring to God, because it is calculated to give the world a gloomy and repulsive idea of religion.  Nor is this view of the subject at all inconsistent with the exercise of sorrow for sin, and feeling for sinners.  Godly sorrow is a melting exercise, which softens the heart, and brings it low before God:  while a sight of the cross of Christ, and a sense of pardoning love, bring a holy calm and heavenly peace over all the soul.  But despondency comes over us like the withering blasts of winter.  It congeals the tender emotions of the heart, and casts an icy gloom over every object.  It hides from our view everything lovely.  It makes us insensible to the mercies of God which he is daily lavishing upon us.  It shuts up the soul to brood alone, over everything dark and hideous.  It is no less unfriendly to the exercise of holy affections than levity of conversation and manners.  Although often created by bodily infirmity, it reacts, and renders disease doubly ferocious.  Yet it is so far under the control of the will, that grace will enable us to subdue it.  There is a very intimate connection between the mind and body.  The one acts upon the other.  Depression of spirits enfeebles all the animal powers; and particularly disturbs digestion, thereby deranging the whole system.  If, therefore, you ever feel a gloomy depression of spirits, try to bring your mind into a serene and grateful frame, by meditating on the mercies you enjoy, and exercising a cheerful submission to the will of God.  Remember that God directs all your ways, and that you have just as much of every comfort and blessing as he sees fit to give you, and infinitely more than you deserve.  Rise above yourself, and think of the infinite loveliness of the divine character.  But, if this is not sufficient, walk out and view the works of Nature; and try to forget yourself in contemplating the wisdom and glory of God, as manifest in them; and the bodily exercise will assist in driving-away this disturber of your peace.  Or, seek the society of some Christian friend, who is not subject to depression of spirits, and converse about those heavenly truths which are calculated to call forth the exercise of love, joy, and gratitude, and make you lose sight of yourself in the fulness and glory of God.  Any violent emotion of the mind, or exercise of strong passions of any kind, is likewise exceedingly injurious to the health of the body.