Eternity In The "Heart of Man"

 What do workers gain from their toil? 10 I have seen the burden God has laid on the human race. 11 He has made everything beautiful in its time..He has also set eternity in the human heart; yet[a] no one can fathom what God has done from beginning to end. 
     
     King Solomon penned these words in the  book entitled Ecclesiates. He sought to understand the way of life and moreover the way of his own life.  Son of David, he inherited the Kingdom David fought for and estblished.  Richer than those around him and embued with wisom far greater than those before him or even those after him he was nevertheless empty of a sort!  Reading these words of his it does not seem that he actually believed with  his whole heart that there was a place for him after his life ended.  Resurrection seemed distant in this thoughts.  Perhaps they were.  Maybe even alien to him altogether. Everything he said that was going to be done was done before and nothing was new. Toil was wearisone, wealth gained  was left to those who did not toil for it and true happiness was to enjoy the day at hand and eating to be done with the joy of the moment.  So why did he say eternity was in the heart?  Did he have a longing or a great chasm that was unfulfilled even with all his wealth and wisdom?  I think he knew he did and it troubled him greatly. 
The "end of the matter he said, was this:  

                  Now all has been heard;
                 here is the conclusion of the matter:
           Fear God and keep his commandments,
                    for this is the duty of all mankind.
14       For God will bring every deed into judgment,
                        including every hidden thing,
                       whether it is good or evil.

     I think he found that even with all he had the best that he could do, was to fear God...to be right with him and make sure that his deeds would be of a worthy nature. For we all will be dust and there is no escape so it is much  better to be before the God of heaven with a clean slate and that only happens with the Son of God (Jesus), entering in and making us righteous by his  blood.