Therefore I went about to cause my heart to despair of all the labour which I took under the sun.
I went about (I turned myself) to cause my heart to despair of all the labour - I gave up as desperate all hope of solid fruit from my labour.
Related Commentaries of Ecclesiastes 2:20
Ecclesiastes 2:20
20 Therefore I went about to cause my heart to despair of all the labour which I took under the sun.