Ecclesiastes 11:8-10

Yea, if a man live many years, let him rejoice in them all; but let him remember the days of darkness, for they shall be many. All that cometh is vanity. Rejoice, O young man, in thy youth, and let thy heart cheer thee in the days of thy youth, and walk in the ways of thy heart, and in the sight of thine eyes; but know thou, that for all these things God will bring thee into judgment. Therefore remove sorrow from thy heart, and put away evil from thy flesh; for youth and the dawn of life are vanity.