One of my favorite passages is the following:
"Man's fate is like that of the animals; the same fate awaits them both: As one dies, so dies the other. All have the same breath; man has no advantage over the animal. Everything is meaningless. All go to the same place; all come from dust, and to dust all return.
"All share a common destiny--the righteous and the wicked, the good and the bad, the clean and the unclean, those who offer sacrifices and those who do not. As it is with the good man, so with the sinner; as it is with those who take oaths, so with those who are afraid to take them. This is the evil in everything that happens under the sun: The same destiny overtakes all.
"For the living know that they will die, but the dead know nothing; they have no further reward, and even the memory of them is forgotten. Their love, their hate and their jealousy have long since vanished; never again will they have a part in anything that happens under the sun.
"Go, eat your food with gladness, and drink your wine with a joyful heart, for it is now that God favors what you do...Enjoy life with your wife, whom you love, all the days of this meaningless life that God has given you under the sun-- all your meaningless days. For this is your lot in life and in your toilsome labor under the sun. Whatever your hand finds to do, do it with all your might, for in the grave, where you are going, there is neither working nor planning nor knowledge nor wisdom.
"I have seen something else under the sun: The race is not to the swift or the battle to the strong, nor does food come to the wise or wealth to the brilliant or favor to the learned; but time and chance happen to them all." (Ecclesiastes 9:1-11NIV)