Ecclesiastes 1

 In reading Ecclesiastes, David J. Ridges explains - 

"An important key to understanding Ecclesiastes is the word “vanity,” as used in one form or another five times in chapter 1, verse 2, and at least thirty-two times elsewhere within the book. If you define the word as “pride,” or “self-aggrandizement,” you will not understand Ecclesiastes. However, if you correctly understand that in Ecclesiastes “vanity” means a state or situation that is “temporary,” “transitory,” or “fleeting,” (see Bible Dictionary, under “Ecclesiastes”), and thus means “the temporary or transitory nature of mortality,” then you will get much more out of it. In fact, look at verse 2 of chapter 1 right now. What it is saying, in effect, is that everything associated with mortal life is fleeting and temporary."  (Ridges, David J. The Old Testament Made Easier Part 3)

We see this in - 

"2 Vanity of vanities [fleeting and temporary], saith the Preacher, vanity of vanities [temporary and fleeting]; all is vanity [everything in mortality is temporary]."  (Ridges, David J.. The Old Testament Made Easier Part 3)

For everyone that experiences opposition in all things, it all has its eternal purpose in all things.