Ecclesiastes 9:5 For the living know that they shall die: but the dead know not any thing, neither have they any more a reward; for the memory of them is forgotten. 6 Also their love, and their hatred, and their envy, is now perished; neither have they any more a portion for ever in any thing that is done under the sun.
Their souls, too?
This obviously conflicts with the words of Jesus in Luke 6:23 about some of the dead -- "your reward is great in heaven".
The book of Ecclesiastes also says that all the works done under the sun are vanity. (Ecclesiastes 1:14, and in many other texts in that book.) Does "all" there really mean "all"?
Was the birth of Jesus vanity?
Were the works of Jesus vanity?
Were the crucifixion and death of Jesus vanity?
Was His resurrection vanity?
The book of Ecclesiastes must be read as part of the poetic wisdom writing, written from a particular perspective, and with a specific knowledge base, realizing it often uses poetic exaggerations to make teaching points. (otherwise, you would be calling Jesus a liar, and saying His work was all vanity, just like everything else.)