So I hated all the fruit (gain) of my labor for which I had labored under the sun, because I must leave it to the man who will succeed me.

For there is a man who has labored with wisdom and knowledge and skill, yet gives his legacy to one who has not labored for it. This too is vanity and a great evil.

If the axe is dull and he does not sharpen its edge, then he must exert more strength; but wisdom [to sharpen the axe] helps him succeed [with less effort].