Sirach 30:21-23

²¹Give not over thy mind to heaviness, and afflict not thyself in thine own counsel.

²²The gladness of the heart is the life of man, and the joyfulness of a man prolongeth his days.

²³Love thine own soul, and comfort thy heart, remove sorrow far from thee: for sorrow hath killed many, and there is no profit therein.