Please read “E1. Meaning to the Meaningless” before reading any of my other articles on Ecclesiastes.
Ecclesiastes 11:7-10

Nobody likes a bitter old man. A bitter old man is even more unlikable when he tries to make everyone around him as unhappy as he is. The writer of Ecclesiastes, because of his sinfulness turned into a bitter old man. In vs. 7-10 of chapter 11 his bitterness causes him to attempt to poison the hearts and minds of young people. He tells them that there will be pleasant days, but there will be many more days of darkness. He tells them the outcome of everything will be meaningless. He tells them be happy while you are young. Follow your heart’s desires, and if your eyes find something attractive, grab hold of it. Remember God will judge you, but do not worry about that. He could give them this advice because he did not believe in life after death; so no matter what the judgment, once you die it will all be meaningless anyway. He tells them not to be anxious, for no matter how wonderful they might think youth and vigor are, even that is meaningless. He must have been the life of every party he ever went to, NOT!

In his Rome prison, Paul was an old man. Like the writer of Ecclesiastes, he understood that life had many dark days; after all, he was suffering in prison. However, there was a big difference, he believed in life after death. He believed because he had met Christ, the resurrected. Paul writes two letters to a young man named Timothy. He loves Timothy, and he wants to help prepare him to live a righteous life. His advice to Timothy is much better than the advice in Ecclesiastes. He tells Timothy “Flee the evil desires of youth and pursue righteousness, faith, love and peace, along with those who call on the Lord out of a pure heart.” (2 Timothy 2:22) Paul knew that life is hard, but he also knew God is good.