Rejoice, O young man, in your youth, and let your heart cheer you in the days of your youth. Walk in the ways of your heart and the sight of your eyes. But know that for all these things God will bring you into judgment.
 Remove vexation from your heart, and put away pain from your body, for youth and the dawn of life are vanity. (ESV)
 Remember also your Creator in the days of your youth, before the evil days come and the years draw near of which you will say, “I have no pleasure in them”;  before the sun and the light and the moon and the stars are darkened and the clouds return after the rain,  in the day when the keepers of the house tremble, and the strong men are bent, and the grinders cease because they are few, and those who look through the windows are dimmed,  and the doors on the street are shut—when the sound of the grinding is low, and one rises up at the sound of a bird, and all the daughters of song are brought low— they are afraid also of what is high, and terrors are in the way; the almond tree blossoms, the grasshopper drags itself along, and desire fails, because man is going to his eternal home, and the mourners go about the streets— before the silver cord is snapped, or the golden bowl is broken, or the pitcher is shattered at the fountain, or the wheel broken at the cistern,  and the dust returns to the earth as it was, and the spirit returns to God who gave it.  Vanity of vanities, says the Preacher; all is vanity. (ESV)