Just as a bird will soar ever higher only as long as it vigorously beats its wings but will begin to fall and descend to earth as soon as it stops its energetic activity, so too it is with man.
As long as he is actively engaged in a vigorous program of character refinement and self-improvement, he will soar to ever-higher spheres of spiritual attainment. When he discontinues his determined efforts, however, and slackens in his quest for self-improvement, he will begin to fall from his previously high plateau of spiritual attainment. ~ R’ Yisrael Salanter zt”l