Ecclesiastes 1:8; Ecclesiastes 1:16; Ecclesiastes 2:15; Ecclesiastes 3:7; Ecclesiastes 7:21

8 All things are full of labour; man cannot utter it: the eye is not satisfied with seeing , nor the ear filled with hearing .
16 I communed with mine own heart, saying , Lo, I am come to great estate , and have gotten more wisdom than all they that have been before me in Jerusalem: yea, my heart had great experience of wisdom and knowledge.
15 Then said I in my heart, As it happeneth to the fool, so it happeneth even to me; and why was I then more wise ? Then I said in my heart, that this also is vanity.
7 A time to rend , and a time to sew ; a time to keep silence , and a time to speak ;
21 Also take no heed unto all words that are spoken ; lest thou hear thy servant curse thee: