Ecclesiastes 11:8-10 ESV
So if a person lives many years, let him rejoice in them all; but let him remember that the days of darkness will be many. All that comes is vanity.
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: English Standard Version 2016