Halakha Amsal 6:6: Mishneh Torah, Human Dispositions

The straight path is the mean disposition found in each and every tendency of all the human tendencies. Such tendency is removed from both extremes an equal distance, and is not nearer to one than to the other. Therefore have the wise men of yore commanded that man should ever review his tendencies,¹Sotah, 5b. C. estimate them, and direct them toward the middle-path so that he will be sound in body. How may one do it? He should not be an excitable person, easily angered; nor like the dead without feelings, but adopt a middle-course, not to become indignant, save only at something big which is worthy enough to be angry at, so that the like should not be done another time. Likewise shall he not crave for aught save the things which the body requires, and without which it is impossible to be, as the subject is spoken of: "The righteous eateth to the satisfying of his soul" (Pro. 13.25). Likewise shall he not continue to fatigue himself in his affairs, save to acquire what is necessary for him to live on for the time being as the subject is mentioned, saying: "A little that a righteous man hath is better" (Ps. 37.16). He should not be too close-fisted, nor yet squander his money, but give Z'dakah within the means of his hand, and lend accordingly to the needy. He should not be too optimistic and playful, nor too pessimistic and mournful, but spend all of his days in good cheer and with a pleasant countenance. So should he measure all the rest of his tendencies. And this path is the path of the wise men. Every man whose tendencies are mean tendencies of the middle-course, is called wise.