19 And who knows whether that person will be wise or foolish? Yet they will have control over all the fruit of my toil into which I have poured my effort and skill under the sun. This too is meaningless.

Read Ecclesiastes 2:19 Using Other Translations

And who knoweth whether he shall be a wise man or a fool? yet shall he have rule over all my labour wherein I have laboured, and wherein I have shewed myself wise under the sun. This is also vanity.
and who knows whether he will be wise or a fool? Yet he will be master of all for which I toiled and used my wisdom under the sun. This also is vanity.
And who can tell whether my successors will be wise or foolish? Yet they will control everything I have gained by my skill and hard work under the sun. How meaningless!