"Since no man knows the future, who can tell him what is to come?" NIV translation
Although there are people with lots of education and knowledge, there are limits to their knowledge such as the fact that they do not know the future. "What would you do today if you knew it was your last day?" is a question that is often asked. We must keep in mind that, for all we know, every day could be our last and so we should live like it. This is what James was talking about when he spoke of our boasting about our future plans (see James 4).
"No man has power over the wind to contain it, so no one has power over the day of his death. As no one is discharged in time of war, so wickedness will not release those who practice it." NIV translation
When we die, our spirit either returns to the Father or awaits judgment. When our time is up, we cannot stop the journey of the spirit. Just like a soldier is retained during wartime, those who battle sin on their own will never be free from it.
"All this I saw, as I applied my mind to everything done under the sun. There is a time when a man lords it over others to his own hurt. Then too, I saw the wicked buried - those who used to come and go from the holy place and receive praise in the city where they did this. This too is meaningless." NIV translation
Here, Solomon speaks of corrupt religious leaders as they saw the poor being oppressed and did nothing. Instead, those who were doing it were praised because they brought offerings to the temple.
"When the sentence for a crime is not quickly carried out, the hearts of the people are filled with schemes to do wrong. Although a wicked man commits a hundred crimes and still lives a long time, I know that it will go better with God-fearing men, who are reverent before God. Yet because the wicked do not fear God, it will not go well with them, and their days will not lengthen like a shadow." NIV translation
Solomon looked at delayed punishment and could not understand why those who do evil things can live a long time. Yet, he knew that, in the end, the punishment would come.