'Laboureth' in the Bible

He that laboureth laboureth for himself; for his mouth craveth it of him.

What advantage is to man by all his labour that he laboureth at under the sun?

What profit hath he that worketh in that wherein he laboureth?

And this also is a painful evil, just as he came, so he goeth, and what advantage is to him who laboureth for wind?

Lo, that which I have seen: It is good, because beautiful, to eat, and to drink, and to see good in all one's labour that he laboureth at under the sun, the number of the days of his life that God hath given to him, for it is his portion.