Ecclesiastes 2:18-20

Then I hated all my labor in which I had toiled under the sun, because I must leave it to the man who will come after me. And who knows whether he will be wise or a fool? Yet he will rule over all my labor in which I toiled and in which I have shown myself wise under the sun. This also is vanity. Therefore I turned my heart and despaired of all the labor in which I had toiled under the sun.