Ecclesiastes 11:9
“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 thine heart, and in the sight of thine eyes: but know thou, that for all these things God will bring thee into judgment.”
Truly the light is sweet, and a pleasant thing it is for the eyes to behold the sun:
But if a man live many years, and rejoice in them all; yet 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 thine 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 childhood and youth are vanity.
Counter-Arguments
The strongest case that this verse does not belong in this theme.

Related Verses
“Go thy way, eat thy bread with joy, and drink thy wine with a merry heart; for God now accepteth thy works.”
“I said in mine heart, God shall judge the righteous and the wicked: for there is a time there for every purpose and for every work.”
“I know that there is no good in them, but for a man to rejoice, and to do good in his life.”
“For he shall not much remember the days of his life; because God answereth him in the joy of his heart.”
“My son, if thine heart be wise, my heart shall rejoice, even mine.”