1. Michael Suderman

5. 13 When all has been heard, the conclusion of the matter is this:
fear God and keep His commands, because this is for all humanity. 
14 For God will bring every act to judgment, including every hidden thing, whether good or evil.
Ecclesiastes 12:13-14

6. Central to the structure of Ecclesiastes is the juxtaposition of the “carpe diem” passages with the enigmatic passages and this juxtaposition creates gaps which the reader has to fill.
(The end of) Ecclesiastes is fundamental to the book in the answer it gives as to how the gaps should be filled.
Ecclesiastes is an ironical exposure of an empiricistic epistemology which seeks wisdom through personal experience and analysis without the “glasses” of the fear of God. This empiricistic epistemology keeps running up against the enigma of life when pursued from this direction and it appears impossible to find a bridge between this enigma and the good that is visible and which the biblical tradition alerts one to.
The resolution of this paradox is found in the fear of God which enables one to rejoice and apply oneself positively to life in the midst of all that one does not understand, including and especially death.
Craig Bartholomew
Reading Ecclesiastes: Old Testament Exegesis and Hermeneutical Theory

7. Ecclesiastes is the juxtaposition of
two ways to respond to the unfairness of life:
carpe diem passages
(i.e., 2:24, 5:18-20)
enigmatic passages (i.e., 7:15, 8:14)
Life is hard and unfair, so “seize the day” and squeeze whatever joy you can out of life.
Life is hard and unfair, so do everything you can to figure out everything.

8. A Carpe Diem passages:
18 Even so, I have noticed one thing, at least, that is good.
It is good for people to eat, drink, and enjoy y their work under the sun during the short life God has given them, and to accept their lot in life.
19 And it is a good thing to receive wealth from God and the good health to enjoy it. To enjoy your work and accept your lot in life – this is indeed a gift from God.
20 These people seldom reflect on the days of their life, because God keeps them occupied with the gladness of heart.
Ecclesiastes 5:18-20
…put your hope in God, who richly provides us with everything for our enjoyment.
1 Timothy 6:17

9. Ecclesiastes is the juxtaposition of
two ways to respond to the unfairness of life:
carpe diem passages
(i.e., 2:24, 5:18-20)
enigmatic passages (i.e., 7:15, 8:14)
Life is hard and unfair, so “seize the day” and squeeze whatever joy you can out of life.
Life is hard and unfair, so do everything you can to figure out everything.

10. Ecclesiastes 12:13-14 “fill the gap.”
Ecclesiastes is the juxtaposition of
two ways to respond to the unfairness of life:
carpe diem passages
(i.e., 2:24, 5:18-20)
enigmatic passages (i.e., 7:15, 8:14)
Life is hard and unfair, so “seize the day” and squeeze whatever joy you can out of life.
Life is hard and unfair, so do everything you can to figure out everything.
Ecclesiastes 12: “fill the gap.”

11. 13 When all has been heard, the conclusion of the matter is:
fear God and keep His commands,
because this is the duty for all humanity. 
14 For God will bring every act to judgment, including every hidden thing, whether good or evil.
Ecclesiastes 12:13-14

12. Ecclesiastes 12:13-14 “fill the gap.”
Ecclesiastes is the juxtaposition of
two ways to respond to the unfairness of life:
carpe diem passages
(i.e., 2:24, 5:18-20)
enigmatic passages (i.e., 7:15, 8:14)
Life is hard and unfair, so “seize the day” and squeeze whatever joy you can out of life.
Life is hard and unfair, so do everything you can to figure out everything.
Ecclesiastes 12: “fill the gap.”