Vanity of vanities, says the Teacher, vanity of vanities! All is vanity. (NRSV 1:2)
Vanity of vanities, saith the Preacher, vanity of vanities; all is vanity. (KJV 1:2)
We're kind of obligated to start off with this one in this section. You know—just to set the mood.
He has made everything suitable for its time; moreover he has put a sense of past and future into their minds, yet they cannot find out what God has done from the beginning to the end. (NRSV 3:11)
He hath made every thing beautiful in his time: also he hath set the world in their heart, so that no man can find out the work that God maketh from the beginning to the end. (KJV 3:11)
"The world" and "a sense of past and future" are actually translations of a word that also means "Eternity" (so, whatever floats your boat here…). The gist of this is that God has given people a sense that there's this immense universe—endless space and endless time—stretching out beyond them. But he hasn't given them the ability to really see it all or know it all. Only God has the ticket for that show.
This is what I have seen to be good: it is fitting to eat and drink and find enjoyment in all the toil with which one toils under the sun the few days of the life God gives us; for this is our lot. Likewise all to whom God gives wealth and possessions and whom he enables to enjoy them, and to accept their lot and find enjoyment in their toil—this is the gift of God. For they will scarcely brood over the days of their lives, because God keeps them occupied with the joy of their hearts. (NRSV 5:18-20)
Behold that which I have seen: it is good and comely for one to eat and to drink, and to enjoy the good of all his labour that he taketh under the sun all the days of his life, which God giveth him: for it is his portion. Every man also to whom God hath given riches and wealth, and hath given him power to eat thereof, and to take his portion, and to rejoice in his labour; this is the gift of God. For he shall not much remember the days of his life; because God answereth him in the joy of his heart. (5:18-20)
This is another one of Ecclesiastes's huge themes—he keeps coming back to it (maybe even beating us over the head with it). If God lets you be contented with the good and simple things—eating and drinking and enjoying your work—then you're blessed. He helps distract you from all the vanity and death.
Better is the sight of the eyes than the wandering of desire; this also is vanity and a chasing after wind. (NRSV 6:9)
Better is the sight of the eyes than the wandering of the desire: this is also vanity and vexation of spirit. (KJV 6:9)
This little quote packs a punch. Ecclesiastes is saying that if you're not appreciating the beauty that's in front of you—observing it and enjoying it just by beholding it—then you're stuck in the world of wandering desires, desperately trying to get pleasure instead of seeing what's right there in front of you.
Go, eat your bread with enjoyment, and drink your wine with a merry heart; for God has long ago approved what you do. Let your garments always be white; do not let oil be lacking on your head. Enjoy life with the wife whom you love, all the days of your vain life that are given you under the sun, because that is your portion in life and in your toil at which you toil under the sun. Whatever your hand finds to do, do with your might; for there is no work or thought or knowledge or wisdom in Sheol, to which you are going. (NRSV 9:7-10)
Go thy way, eat thy bread with joy, and drink thy wine with a merry heart; for God now accepteth thy works. Let thy garments be always white; and let thy head lack no ointment. Live joyfully with the wife whom thou lovest all the days of the life of thy vanity, which he hath given thee under the sun, all the days of thy vanity: for that is thy portion in this life, and in thy labour which thou takest under the sun. Whatsoever thy hand findeth to do, do it with thy might; for there is no work, nor device, nor knowledge, nor wisdom, in the grave, whither thou goest. (KJV 9:7-10)
Ecclesiastes is urging us to seize the day again—before death falls and everything disappears.
Just as you do not know how the breath comes to the bones in the mother's womb, so you do not know the work of God, who makes everything. (NRSV 11:5)
As thou knowest not what is the way of the spirit, nor how the bones do grow in the womb of her that is with child: even so thou knowest not the works of God who maketh all. (KJV 11:5)
Like in Ecclesiastes's quote about how God put "Eternity" into the mind of man, this quote hammers home how ignorant we are about how things really work.