In conclusion Solomon repeated his original thesis (v. 8; cf. 1:2) and his counsel in view of life's realities (vv. 13-14). In between these statements he set forth his source of authority for writing what we have in Ecclesiastes (vv. 9-12).
12:8 All human work (1:12-6:9) and wisdom (6:10-11:6) are ultimately futile (i.e., lacking ability to produce anything of ultimate worth in this life).
12:9-12 The phrase "these collections"(v. 11) refers to other collections of wise sayings (e.g., Job and Proverbs). Ultimately all wisdom comes from God. "Goads"(v. 11) are prodding sticks, and people who master this wisdom literature are similar to "well-driven nails"in that they are stable and secure.
"Beyond this"(v. 12) evidently refers to beyond the wisdom literature that God has revealed, in view of verse 11. Solomon warned his disciple that looking elsewhere in other books for divine wisdom would only wear him out. This verse does not say that all study is tiring, though that is true. It means that study of books other than what God has revealed to learn wisdom is an endless, wearisome occupation. This is not to say we should avoid reading books other than the Bible. Nonetheless the main place to look when you want to find true wisdom is in God's Word.
12:13-14 Solomon's concluding statement reiterated what he said earlier (2:24-26; 7:15-18; 11:9-10; 12:1) and elsewhere (Prov. 1:7; cf. Job 28:28). Trust and obedience are what everyone owes God in view of future judgment.
"Though a future judgment after death is indeed the solution to the enigma Solomon had observed in the unequal distribution of justice in human history (cf. 7:15; 8:14), no evidence suggests that Solomon believed in [i.e., was aware of] such a judgment. Life after death was as enigmatic to him (cf. 11:8) as the unequal distribution of justice. His emphasis was on this life(under the sun') and its opportunities for service (cf. 9:10; 12:1-7) and enjoyment (cf. 2:24-26; 3:12, 22; 5:18-20; 8:15; 9:7-9; 11:7-10); he thought life after death offered no such opportunities (cf. 9:5-6, 10). Therefore he did not comment on any differences afterdeath between the righteous and the wicked, the wise and the fools, man and beast."82
With the greater light of revelation that we enjoy it is even more incumbent on us to follow Solomon's counsel. We should be content to leave the enigmas of life in God's hands. We should also follow Solomon's wise counsel to enjoy life as God enables us to do so and to serve God acceptably while we can.
"What is the profit' of living? What does a man get for all his work? He gets the living God! And his whole profit consists of fearing Him and obeying His Word."83